UNIVERSITY OF CALIFORNIA COLLEGE OF AGRICULTURE AGRICULTURAL EXPERIMENT STATION BERKELEY, CALIFORNIA NECTAR AND POLLEN PLANTS OF CALIFORNIA G. H. VANSELL Revised by G. H. VANSELL and J. E. ECKERT APIARY IN THE SAGE REGION OF SOUTHERN CALIFORNIA BULLETIN 517 October, 1931 Revised April, 1941 UNIVERSITY OF CALIFORNIA BERKELEY, CALIFORNIA CONTENTS PAGE Nectar secretion 7 Pollen and pollen production 14 Plants of possible injury to bees 16 Nectar and pollen-yielding plants 18 NECTAR AND POLLEN PLANTS OF CALIFORNIA G. H. VANSELL 1 Eevised by G. H. VANSELL and J. E. ECKERT 2 Commercial honey production depends upon the availability of suffi- cient flowering plants for the honeybee colony to store a surplus of honey beyond its own food requirements. A knowledge of the nectar and pollen plants of any particular region, their time and period of blooming, as well as the relative value of each species for pollen or nectar during the changing seasons, is therefore of importance to the successful man- agement of bees. In California, conditions are so varied in soil and climate as to pro- duce not only an exceptionally large number of pollen- and nectar-pro- ducing plants but also to influence in a marked degree their production of nectar and pollen from season to season. Natural and cultural con- ditions are ever changing and it is normal for new species of plants to crowd out old ones just as under rotation one cultivated crop succeeds another. These changes make it difficult to be positive in statement as to the actual value of a given plant as a producer of nectar or pollen in any particular locality. Because of the great area over which bees habitually range, it has been found to be impractical to raise plants especially for the honey or pollen which bees might obtain from them. For example, it is generally estimated that one strong colony is needed for each acre of fruit trees for proper pollination and from this acre the colony may gather little or no surplus. One can encourage the growth of nectar- or pollen-produc- ing plants for covercrops and other purposes, and thus secure added forage for the bees as a secondary consideration, or else move the col- onies to a more favorable locality. Of the thousands of species of plants that grow in California, at least 200 are here considered to be of sufficient importance to mention as yielders of pollen or nectar. The major honey sources are confined to the plants of only 8 of the 136 families listed for the state. Hundreds of flowering plants may yield some nectar or pollen and yet each may be too scarce in a given locality or yield too meagerly to be of material importance from the viewpoint of bee culture. 1 Kesearch Associate in the Experiment Station and Associate Apiculturist in the Pacific States Bee Culture Field Laboratory of the United States Department of Agriculture Bureau of Entomology and Plant Quarantine. 2 Associate Professor of Entomology and Associate Apiculturist in the Experiment Station. [3] 4 University of California — Experiment Station Bees may secure honey from plants of widely different types of growth, as for example from the lowly carpet grass, the bushy manza- nita, and the giant blue gum. The mere fact that a plant is blossoming in abundance, either under irrigation or in a wild state, gives no assur- ance that honey may be available. Among the attributes of a plant which result in its being a honey pro- ducer are: (1) nectar secretion, (2) suitable structure for collection by the bee, (3) sufficient sugar in the nectar to be attractive, (4) abundance of the plant and of its nectar. The ten most important sources of commercial honey in California are alfalfa, the sages, orange, star thistle, wild buckwheats, manzanita, cotton, lima bean, blue curls, and eucalyptus; of these the sages, wild buckwheats, manzanita, and blue curls are native. The approximate dis- tribution of the important honey sources is shown in the text figures. The sage family is represented by many species. The three most productive sages, Salvia mellifera (black sage), 8. apiana (white sage), and 8. leucophylla (purple sage) occur along the coast from the San Francisco Bay region, south. Creeping sage, 8. sonomensis, and desert sage, 8. mohavensis, are also important in isolated areas, yielding a typical quality of sage honey. The "sagebrush" of Nevada, Utah, Wyoming, and other western states is not true sage, but belongs to an entirely different family of plants, and yields no nectar of any consequence. The "Nevada sage honey," sold commonly in California as a competitor of true sage honey, comes primarily from alfalfa. Dozens of other plants in restricted localities may yield commercial quantities of honey in favorable years and many rank high in the esti- mation of the beekeeper because of their value to the bees as a source of food for building up the colony early in the spring or to carry it over the winter period. The blossoms of the deciduous fruit trees and certain truck crops are very attractive to bees and come at a time of the year when the pollen and the small amount of nectar stimulate the production of brood and thus aid in building up the colony for honey production later in the season. In turn, the bees cross-pollinate the blossoms and in this way render an indispensable service to agriculture. The bees get only a rela- tively small portion of their total supply of pollen and at times an insig- nificant amount of nectar from the countless ornamental plants grown for purely decorative purposes. These plants seldom occur in sufficient quantity to be of much importance to the honeybee. Many of the culti- vated field crops yield little or no nectar. However, certain cultivated plants, such as citrus, alfalfa, lima bean, cotton, deciduous fruit trees, and cucurbits are important sources of pollen or nectar during their Bul. 517] Nectar and Pollen Plants of California 5 blooming periods. The practice of cutting alfalfa hay before it blooms and the reduction in the acreage of alfalfa during the last five years has reduced to a considerable extent the importance of alfalfa as a honey plant. However, it still ranks high among the list of plants in the state as a producer of honey in commercial quantities. The wild buckwheats, Eriogonum spp., cover a vast acreage in Cali- fornia but are not dependable yielders of nectar. At times their blossoms literally cover thousands of acres without attracting the honeybees to them. They should not be confused with the annual buckwheat grown agriculturally in New York and other eastern states. The plants are en- tirely different; our species are, in the main, perennial woody bushes in the chaparral of our southern hills and plains. Such grains as wheat, barley, oats, and rice do not attract the honey- bee and the acreage they cover is unimportant except for the weeds that grow in the spring or that follow the harvest. California may be divided roughly into three series of belts with ref- erence to nectar sources : coastal, intermountain, and transmountain (fig. 1). The coastal belt, extending between the Pacific Ocean and the summits of the coast ranges, shows three distinct types of flora, divided latitudinally about the region of the San Francisco Bay. The intermoun- tain belt comprises the Sacramento, San Joaquin, and Antelope valleys and the surrounding elevations. This intermountain area, in particular, is made up of a series of belts running north and south at successively higher elevations from the valley floor to the summits of the ranges, and each of them shows a characteristic flora which is destined to be increas- ingly important as sources of honey. East of the high Sierra Nevada lies the Owens Valley. At the northern end of the Cascade Range are the valleys of Siskiyou and Mocloc counties, while in the southeastern end of the state is the Imperial Valley. These three areas are here spoken of collectively as the transmountain honey areas. In the past, various authors have divided the state into belts or areas on a basis of the distribution of honey plants. They fall logically into these seven areas : (1) Imperial Valley, (2) southern orange-belt coun- ties, (3) southern coast counties, (4) San Joaquin Valley, (5) Sacra- mento Valley, (6) San Francisco Bay and the cutover redwood area of the coast range, and (7) mountain counties all grouped under the four natural belts shown in figure 1. The names of the chief sources of honey in various places have been written in this general map. Very few areas in the state have a continuous succession of blooming plants and as a result commercial beekeepers practice migratory bee- keeping, moving their bees from three to five or more times during the growing season. 6 University of California — Experiment Station The list of plants included in this publication is not complete and the designations of their relative importance may change from season to season, varying with climatic and cultural conditions and practices. Dis- tribution maps are used to indicate roughly where the plants occur in sufficient abundance to be important. a/fa/fa, stveet c/orer * i \ \ =*s ~~H 1 V ^ 1 1 ^ ( \ CN \ ^ \ \ ^ 1 •^ \ 1 "3> \* V- 1 \t/?/st/e, ^ \ ^. \ a/ fa /fa %\^ o/fa/fa, //ma />ea/?s ^~ a/ fa/ fa, £/ve car/ a/to 1 , '^W/ c / ot £ r after weeds ^ , \\ ora/jyes co/toa, a/fa/fa ' t oraages \ \ \ Fig. 1. — The general regions of California with their major honey sources. a/fa/fa The content of this bulletin has been compiled primarily from the per- sonal observations and experience of the authors and from numerous printed sources, as well as from correspondence and interviews with bee- keepers throughout the state. The illustrations used are original unless otherwise mentioned. The classification and nomenclature follows, for Bul. 517] Nectar and Pollen Plants of California 7 the most part, Jepson's Manual of the Flowering Plants of California? which the reader should consult for more specific information on life zones, distribution, and plant populations. A list of the nectar and pollen plants discussed, with their scientific names, is given in table 3. Also given there are some of the principal characteristics of the plants in rela- tion to beekeeping, summarized for ready reference. The honey colors are based on the Pfund honey-grader scale. NECTAR SECRETION The secretion of nectar is one of the remarkable functions of plant life. It consists primarily of the production of a sugar solution secreted from special organs of the plant known as nectaries. These organs are located in various parts of the flower — on the stem, leaf, node, or bract of the plant; they are known as extrafloral nectaries when they occur elsewhere than in the flower (fig. 2). The physiology of nectar secretion is of particular interest to the plant physiologist or botanist, while the environmental factors affecting nec- tar flow are of especial significance to the beekeeper. The discussion of this subject will, therefore, be confined to those factors of greatest im- portance to the honey producer. The function of nectar secretion has been considered by many to be a means of attracting insects to plants in order to assure the proper dis- semination of pollen and the cross-fertilization of the flower. Many plants require cross-fertilization in order to be fruitful and must depend upon insects for this necessary service. Other plants are self -fertile or are wind-pollinated and while they are not dependent on insect visits for proper fertilization, they are often benefited by them. It is difficult to explain the purpose of extrafloral nectaries on the leaves and bracts of cotton. Some botanists believe the extranuptial nectar glands were originally water glands that have subsequently acquired the function of secreting sugar. All plants that produce pollen do not necessarily produce nectar and bees often collect little or no pollen from plants that yield nectar in abundance. In the economy of the honeybee colony, honeybees visit many species of plants for nectar only and secure pollen only from other plants. In some instances, also, a species of plant may be benefited by the accidental transference of pollen from other plants of the same species while the bee is gathering only nectar and seldom ever secures a load of pollen. Alfalfa is a notable example of this type of plant, in 3 Jepson, W. L. A manual of the flowering plants of California. 1238 p. Associated Students Store, University of California, Berkeley, Calif. 1925. 8 University of California — Experiment Station the majority of locations. In the Imperial Valley bees have been ob- served to gather considerable pollen from alfalfa. It is evident that the function of nectar secretion would vary not only in different species of plants but also between members of the same species, according to the vigor of the plant, and such environmental f ac- Fig. 2. — Showing drops of nectar on leaves of Acacia Ion gi folia. tors as the temperature, humidity, soil type and soil moisture, hours of sunshine, and altitude. A change in the relative value of one or more of these factors may alter markedly the amount and quality of the nectar produced. Since weather conditions are seldom the same for suc- cessive seasons, plant growth will vary accordingly and nectar secretion is tied up intimately with the physical functions of plant growth. A wide range between day and night temperatures is supposed to be favorable for nectar secretion, although it has been observed in various parts of California, as well as in other states and Canada, that the great- est amount of honey is produced during heat periods when both day and night temperatures are high. A continuation of these high temperatures, however, tends to hasten maturity, and shorten the period of the nectar Bul. 517] Nectar and Pollen Plants of California flow. The character of the soil and soil moisture affect the quantity and quality of the nectar. Certain plants, such as heathers, yield well on acid soils while others, such as certain sages, do their best on lime soils. Sur- rounding Brawley, in the Imperial Valley, the heavy soils, which crack badly and therefore tend to dryness, appear consistently to give larger alfalfa honey yields than the lighter soils. Some cultivated plants, such as alfalfa, are adapted to a variety of soil types at different elevations. Its nectar varies not only in quantity but also in quality as well. Alfalfa commercial honey in Nevada (at 5,000 feet elevation) is white while in Table 1 Percentage of Sugars in Orange Nectar* Sample no. Sucrose Dextrose Levulose Total sugar 1 2 14 9 7.4 6.9 10. 6 8.8 6.2 8.9 5.63 5.64 4 42 6.04 7.23 7.23 8.05 3 70 4 36 5.08 4.26 4 07 4.07 5 15 24 23 17 40 3 16 40 4 20 90 5 6 7 20.10 17.50 22 10 * The nectar was secured in Orange County by Wra. G. Watkins of the Pacific Coast Bee Culture Field Station, United States Department of Agriculture. The chemical analyses were made in the laboratory of Prof. D. R. Hoagland, University of California, Berkeley. Some time elapsed between the collection and the analysis of the nectars, during which they were preserved with toluol in tightly stoppered glass containers. the Imperial Valley, alfalfa honey is light amber in color; 4 again, it is lighter in color on sandy soils and darker on heavier soils. Alfalfa nec- tar, however, appears to be invariably water white when collected by hand. Sweet clover on the northern plains (Dakotas and Canada) under long daylight exposure yields nectar much more copiously than farther south. Nectars vary in chemical composition with the plant source as well as with environmental conditions. Nectar is primarily a solution of sugars together with various mineral elements, certain enzymes, coloring mate- rials, and aromatic substances which give to honeys their characteristic flavors. The sugars are mainly sucrose, dextrose and levulose as illus- trated by the analysis of samples from navel and Valencia oranges, hand-collected in April, 1939 (table 1). On the average, about 80 per cent of the total nectar was water. In five out of the seven samples, the invert sugars exceeded sucrose in quantity. The well-known fact that ripened honeys vary in the proportion of the sugars is no longer mysterious since the original nectars show some- 4 Van sell, G. H. The honeybee in relation to alfalfa in California. Jour. Econ. Ent. 21:411-13. 1928. 10 University of California — Experiment Station what the same differences. The invert sugars in nectar of a eucalyptus (blue gum) over a period of five consecutive days ranged from 6.47 per cent to 9.92 per cent, while the ratio between invert and total sugars varied from 1 : 1.566 to 1 : 2.192. 5 Numerous ref ractometer examinations of western nectars and honey- dew revealed a variation in the percentage of sugar in those from dif- Concentration per cent 65 60 Plant Red filaree Willow Flat-top buckwheat 58 Wild alfalfa (Bird's-foot trefoil) 52 Dandelion 51 Cherry (sweet) 50-60 Apple 50 Chickweed 50 Common mustard 50 Flax 49 Horehound 48 White sage 48 Castor bean (extrafloral glands) 41 Cantaloupe 46 Black sage 45 Toyon 44 Acala cotton (extrafloral glands) 41 White and Ladino clover .... 41 Tamarisk 38 Star thistle 38 Pink buckwheat (wire weed) 37 Incense cedar (honeydew) . . 36 Concentration Plant per cent Alfalfa and sweet clover .... 35-60 Almond 35-50 California buckeye 33-51 Fenugreek 32 Creeping sage 32 Monkey plant 32 Annual sunflower 31 Red gum (Eucalyptus rostrata) 30 Blue curls 27 Tree tobacco 26 Turkey-mullein 25 Cotoneaster (Cotoneaster Harroviana) 25 Acala cotton (blossom) .... 22 Manzanita 16-50 Peach and nectarine 16-40 Locoweed (Astragalus spp.) . 16-59 Avocado 15 Cherry (sour) 15-40 Eucalyptus 13 Plum 10-60 Orange 10-30 Apricot 5-25 Pear 4-30 f erent sources. Most of the samples were secured from visiting bees, but in some cases the nectar was collected by hand from the nectaries. The current average values from the determinations in California are shown above. Because the plants were not all under the same environment, nor pro- ducing at the same time, the values are comparable only in a general way. Nevertheless, these concentration figures afford a basis for a plausible explanation of bee activity in their apparent selection or neglect of certain sources within flight range. Similar investigations also indicate a variation in nectar sugar con- G California Agricultural Experiment Station. Report of the Agricultural Experi- ment Station of the University of California 1926-27:75. (Out of print.) Bul. 517] Nectar and Pollen Plants of California 11 centration between species within a genus and even between varieties. Examples of such data are recorded in table 2. 6 Available information on the source and composition of colors in nec- tars and honeys is incomplete and indefinite. Hand-collected nectars Table 2 Sugar Concentration of Nectar from Plants within Certain Classification Groups Plant Average per cent concentra- tion Place and time of collection Blackberries: Himalaya Evergreen Cherries: Pie Black Republican. . Astragalus (locoweeds) leucophyllus trichopodus Hendersonii Hornii pachypus Pears: Bartlett Howell Burkett Cornice Plums: Maynard Gee Whiz El Dorado Miss Edith Shiro Etta First Milton Kelsey Better than Gold. . Kingdom Come. . . Sages: Creeping Black White 32 45 48 j Oregon, June 26, 1937 Corvallis, Oregon, April 15, unirrigated valley land Various Cherry blocks side by side on Medford, Oregon, morning of April 18, 1938. Nectar hand-collected. All in one area but in separate orchards on sloping fields Davis, California, March 17, 1935. Nectar hand-collected. No nectar present in three varieties, as indicated. Varieties were on level ground in the same orchard, with little variation in soil, irriga- tion, and humidity Various from many floral sources appear to be water white although the com- mercial honeys resulting therefrom may have considerable color. The coloring components are often unstable in that the colors of collected 8 All records from Oregon were obtained cooperatively with the Oregon Agricul- tural Experiment Station. 12 University of California — Experiment Station samples tend to darken with age. For example, poinsettia nectar was white when collected but became a golden light amber after six years, while that of the California buckeye changed from light amber to a dark amber shade within a year. The samples were stored in tightly corked vials, in total darkness, and were preserved with toluol. A simi- lar trend in color change has been observed in various honeys. Certain honeys granulate or candy readily. Each specific honey plant affords a typical honey of fairly definite levulose, dextrose, and sucrose content. Granulation is occasioned by the dextrose's crystallizing out of solution, and the speed of granulation is a rough indication of the amount of this sugar present. When honey granulates, the crystals con- tain less water than the original liquid honey, so the part still in solution is virtually diluted with water and will then ferment more readily. Beutler 7 of Germany has shown a marked difference existing in nectar concentration during periods of wet and dry atmosphere. This condition obtained in plants fully protected from rain. Beutler furthermore shows a striking difference in nectar sugar concentrations between plants under identical conditions ; for example, a horse chestnut with 75.2 per cent sugar concentration and a fritillary with but 10 per cent. Recent studies of nectar and its secretion in California and Oregon have re- vealed a wide variation of sugar concentration : from 2 per cent in Bart- lett pear to 70 per cent in red filaree. This explains, at least in part, why bees show preference for certain plant nectars. Park 8 of Iowa has shown that nectars in varieties of gladiolus plants differ in sugar con- centration. In this work apparently the age of the blossoms was not con- sidered as a factor. Humidity and the rate of evaporation affect the concentration of nectars after they are secreted. Apricot nectar, which is low in sugar concentration when secreted, may remain too low in concentration to be attractive to bees during periods of high humidity. The structure of blossoms greatly affects the rate of water evaporation or its absorption with changing weather conditions. Wind has its effect upon bees and nectar secretion. A wind that is blowing over 12 to 15 miles per hour greatly retards flight. In a windy area the presence of trees helps bees; they may often be seen traveling along the leeward side of a hedge to and from a pasturage. In the Sacra- mento Valley region, winds from the north and southwest are frequently of too high velocity for best results with bees; of the two, however, the north wind is to be preferred, because high temperatures, which are 7 Beutler, Ruth. Ecological observations on the composition of nectar. (Translated title.) Soc. Morph. and Physiol. Proc. [Munich] 39:41-48. 1929. 8 Park, O. W. Studies on the sugar content and yield of nectar from different varie- ties of Gladiolus primulinus. Jour. Econ. Ent. 23 : 438-39. 1930. Bul. 517] Nectar and Pollen Plants of California 13 favorable for nectar secretion, usually accompany the north winds dur- ing summer. Humidity is very low when the north wind blows and rela- tively high during south winds, a factor affecting the sugar concentration in nectar after secretion. Rainfall also has much to do with the availability of nectar since soil moisture is essential for the release of food used in the normal growth and functions of the plant. The beekeepers in the sage ranges have come to predict their summer crop by the amount of rain received before definite dates in early spring. The mesquite plants in southeastern Cali- fornia may burst into blossom and yield nectar after each belated shower. Even under irrigation the light application of water following winters of low precipitation markedly affects the honey crop. The actual growth and vigor of the plant is governed by the presence of moisture at the proper time; but even after sufficient growth is attained to give copius blossoming, the secretion of nectar appears to be, in the case of many plants, largely dependent upon rain during the blossoming period. However, so many other factors also influence nectar secretion that it is perhaps unsafe to make too positive a statement as to the exact cause of failure of a plant to secrete. The works of Kenoyer, 9 Hambleton, 10 and Lundie, u on weather records in relation to honey crops should be con- sulted for details on this subject. Conditions are, of course, too varied in this state to warrant the universal application of these conclusions. Rainy days are generally unfavorable for field work on the part of bees, yet M. C. Richter reported that on the coast at Big Sur large daily gains were frequently made during misty rainfalls. As a rule, nectar secretion, or at least gain in hive weight, is almost stopped by rain, with a gradual recovery for about three or four days after the weather has settled. Formerly, in the San Joaquin Valley areas, with a high water table, several weeds, among them spikeweed (Centromadia) and jackass clover (Wislizenia) , yielded nectar abundantly, while at present with a rap- idly lowering water level, nectar secretion is often negligible. Alfalfa honey in this valley is produced in larger amounts during the dry seasons. The phenomenon of nectar secretion has not been sufficiently studied by plant physiologists; observations by the beekeeper are largely super- ficial, and more fundamental studies of nectar secretion are needed. The 9 Kenoyer, L. A. Environmental influence on nectar secretion. Iowa Agr. Exp. Sta. Res. Bul. 37:219-32. 1916. 10 Hambleton, Jas. I. The effect of weather upon the change in weight of a colony of bees during the honey flow. U. S. Dept. Agr. Dept. Bul. 1339:1-52. 1925. 11 Lundie, A. E. The flight activities of the honeybee. U. S. Dept. Agr. Dept. Bul. 1328:1-37.1925. 14 University of California — Experiment Station nectar goes to waste as far as man is concerned unless harvested by the honeybee. Beekeeping can be made more stable economically by addi- tional knowledge of nectar secretion. The failure of the flow for no ap- parent reason often discourages beekeepers. POLLEN AND POLLEN PRODUCTION The honeybee colony secures its food requirements from three prin- cipal sources — pollen, nectar, and water. In the absence of nectar, the bees may live on honeydew or survive normally on a solution of cane or beet sugars. While some substitutes have been found for pollen, none have been discovered of sufficient value to take its place in the general economy of the hive. The carbohydrates are energy-producing foods and during the quiescent broodless period of winter a colony may live for many months on honey or sugar syrup. In order to rear brood, however, the bees must have access to certain proteins, minerals, and other sub- stances which are found in pollen of plants. The bees collect and store pollen in the combs of their brood nest in excess of their daily needs. For this reason a sufficient pollen supply is just as essential to the wel- fare of a colony as nectar. In the fertilization of plants the pollen must usually come from within the same species since different species as a rule do not ordinarily cross ; but in numerous instances of self -sterility pollen from a different indi- vidual of the same species is necessary. Pollen is carried by a number of agencies including insects, particularly the pollen or nectar feeders. Honeybees are extremely important in the general realm of pollen dis- tribution among plants and are becoming even more so with our present concentration of specialty crops into areas under cultivation practices. Pollen plants always produce pollen in great abundance above their actual needs and in the collection of this excess pollen the bees distribute pollen from blossom to blossom and thus maintain an intricate balance between plant and animal life. It is indeed fortunate for the consumma- tion of plant fertilization that bees absolutely require pollen for their very existence. Where bees are lacking in sufficient numbers to effect the proper pollination of various fruit, vegetable, and seed crops, the grower either supplies the deficiency with package bees or rents a suffi- cient number from beekeepers. In like manner, the beekeeper may move his bees from one location to another in order to provide a more favor- able supply of pollen to meet the needs of his colonies. Pollens from different species show a wide range in physical and chemical composition. All beekeepers are familiar with the range in the color of pollen from white through the spectral colors to almost black. Only preliminary knowledge of the wide variation in the chemical com- Bul. 517] Nectar and Pollen Plants of California Ops. • 0> & 15 Fig. 3. — Photographs of pollen grains, indicating comparative size and shape: (a) cherry, (&) almond, (c) hollyhock, (d) olive, and (e) date palm. Magnification of all, x 250. (From Ext. Cir. 62.) position is known today. It seems probable, however, that it may require much more of some kinds of pollen than of others to provide the neces- sary food requirements; for instance, analyses of corn pollen indicate a very large proportion of starch, which according to some authorities 16 University of California — Experiment Station is not utilizable by the honeybee. Demonstration of the fact that the yellow color of beeswax is derived from contact with certain pollen grains has led to the discovery that these pollens are perhaps the most prolific source of carotin known to science. Carotin, so closely associated with vitamin A, is highly important in the diet of animals. Pollens vary in size, shape, and surface markings (fig. 3) as well as in color and chemical composition. The physical characteristics are often typical of the plant species as the pollen grains are evidently modified to meet the needs of the flower in the process of fertilization. A careful study of these physical characteristics often reveals the plant source and thus the pollens gathered by the honeybee can be made to serve as a key to the identity of the pollen-bearing plants in the region in which they were collected. Plants do not all yield comparable amounts of pollen and therefore as far as beekeeping is concerned they assume varying positions of im- portance in practical application. Especially prolific as bee sources of pollen are deciduous fruits, mustards, corn, dandelion, maples, rabbit- brush, olive, star thistle, and yellow sweetclover; while in comparison to the above, navel orange, most vetches, figwort, manzanita, and ma- drone provide little or even none. The reason it is so difficult to build up colony populations in many instances is the lack of an adequate supply of pollen. Bees consume surprisingly large amounts of pollen ; a pollen trap on one colony at Davis has yielded as much as 1% pounds of pollen in one day. When a surplus over daily needs is gathered, the bees store it in the combs as a reserve supply. The reserves quickly disappear during periods of inclement weather, which causes complete cessation of brood rearing. A prolonged scarcity of pollen, irrespective of plentiful honey stores, results, during the active season, in colony dwindling within four to six weeks. The importance of prolific pollen plants which blossom at the proper time cannot be stressed too fully. PLANTS OF POSSIBLE INJURY TO BEES Many beekeepers have experienced the sudden disappearance of the working forces of their colonies or have noted an abnormal death rate of the brood through some obscure cause. The numerical population of a colony may dwindle over a period of a few days or weeks or may be reduced drastically within a shorter time. Dead bees may be in evidence in the colony or at the entrance or there may be no tangible evidence at hand except their very absence from the hive, without any evidences of swarming. Such a loss at a critical period means the failure of a honey crop since to 8 weeks is generally required to rebuild the colony to Bul. 517] Nectar and Pollen Plants of California 17 storing strength and the honey season may have passed. At times entire apiaries may be killed out and the symptoms do not in any way conform to those of the known bee diseases. Among the causes for a high adult bee death rate are chemical poison- ing following the application of poisons in the attempted control of in- sect pests, a pollen shortage at least six weeks prior to a noticeable decrease in colony population, and plant poisoning. Fortunately for the beekeeping industry, there are not many plants that produce pollen ,or nectar that are injurious to the honeybee and those that are destructive are often confined to fairly definite situations. At least four plants are recognized as responsible for injury to bees in the west : locoweeds, death camas, veratrum or corn lily, and the Cali- fornia buckeye. The locoweeds thrive in the drier portions of the state as well as the foothill sections, and only under special climatic condi- tions which retard or prevent the growth of other pollen — and nectar- producing plants do they become very attractive and injurious to the honeybee. Reports of injury to bees from this plant source have been received from Tulare, Fresno, Santa Barbara, Orange, Los Angeles, and Riverside counties, from western Nevada, and from isolated areas in southern Oregon. The many species of the plant appear to be spotted as to distribution, the factors controlling their peculiar occurrence being obscure. Not all of the members of the genus to which these plants be- long, and perhaps the plants within a genus, are poisonous even when eaten by livestock. One characteristic of locoweed poisoning of bees is that a large portion of the brood dies in the late pupal stage. The adult bees feeding on nectar generally die in the field, as in chemical poisoning. Recent work by independent investigators in western United States indicates a connection between the selenium content of the soil and plants and their toxicity to livestock. The selenium content of the top soil appears to be greatly increased by the lifting through plants of this element from selenif erous subsoil. Once selenium is in the top soil it may appear in abnormal amounts in the seeds and tissues of several species of plants. Whether there is any relation between selenium and the ob- served instances of locoweed poisoning of bees remains to be demon- strated. Veratrum calif ornicum, sometimes called corn lily or false hellebore, occurs in wet flats and about springs; is a characteristic plant of mead- ows in the Sierra Nevada at 4,500 to 8,500 feet, also in the north-coast ranges and high mountains of southern California; hence, it does not invade the better beekeeping locations. Colonies affected by veratrum poisoning rapidly lose in numerical strength over a period of days and individual bees may be found clinging to the plant, dead or in a stupor. 18 University of California — Experiment Station Numerous bees die in the hive and piles of dead are common at the hive entrance. Not much is known about the effects of death camas on the honeybee colony and the symptoms may often be confused with locoweed poison- ing since both types of plants grow in much the same locations. The California buckeye covers many thousands of acres in the foothill sections of the coast ranges and the Sierra Nevada as indicated in figure 18. The bloom of this plant is very attractive to bees and the effect of the pollen or nectar on the adult bees and developing brood proves fatal to hundreds of colonies every year. The field force dwindles away but not so fast as with locoweed or veratrum poisoning. The greatest injury is caused by some toxic element in the pollen which so affects the queen that there is a very high mortality in the eggs she produces and in the resulting larvae. Many of the few bees that do mature in a badly "buck- eyed" colony emerge deformed, and unable to walk or to fly. Additional evidence indicates the presence of substances in pollen and in extracts of the nuts that are toxic to the larvae, if fed to them. Many of the field bees take on the aspects and symptoms of paralytic bees, become dark and shiny through the loss of hair, and shake and shiver until they die an untimely death. Generally, piles of dead and deformed bees, with a sprinkling of paralytics among them, are found at the entrances of badly affected colonies. The California buckeye is undoubtedly the greatest cause of loss of bees from plant poisoning in California. Its presence in the foothill areas^ and even at points along the stream beds where it invades the valleys makes these sections largely unfit for beekeeping during the blooming period which coincides with that of several more important honey plants. In addition to the four plants just described as being poisonous to bees, members of the genus Solanum or nightshade, the western azalea, Rhododendron occidentale, and the black locust are also suspected of being injurious to bees, but without much substantiating evidence. No ill effects to man have ever been traced to honey collected from plants that are injurious to the honeybee in California. NECTAR AND POLLEN-YIELDING PLANTS Acacias. — Of the many species of Acacia in California, sixty or more are introduced. The natives are apparently of far greater importance for nectar than the exotics because they secrete more freely. Among the 12 Vansell, Geo. H., Wm. G. Watkins, and L. F. Hosbrook. The distribution of Cali- fornia buckeye in the Sierra Nevada in relation to hone^ production. 30 p. Pacific States Bee Culture Laboratory, Davis, Calif. (Litho-printed.) Bul. 517] Nectar and Pollen Plants of California 19 native species are notably catclaw, A. Greggii; huajillo, A. Berlandieri; and A. Farnesiana. Catclaw is a heavy yielder under optimum condi- tions. In the southeast part of the state (Colorado Desert), where it is also known as devil's claw and ramshorn, this plant occurs abundantly along washes, where it constitutes, along with mesquite, the chief native nectar source. Texas catclaw, Acacia Wrightii, is reported to be the source of the greater bulk of the catclaw honey in southwest Texas. Many black acacia trees (Acacia melanoxylon) occur in Davis where a bee is seldom observed on them. The nectaries of the majority of the acacias are extrafloral (fig. 2) and those of certain species, among them A. longifolia, secrete abundantly before the blossoms open. From some of the acacias, the pollen pellets as collected by bees are white to light yellow in color. 13 Alder. — Alders are widely distributed along stream beds and in moist places from sea level to high altitudes. They bloom in early spring and provide an abundant source of yellow pollen. Alfalfa. — Alfalfa grows practically everywhere in California, espe- cially in irrigated areas. The acreage of alfalfa is subject to some fluctua- tion but over a ten-year period will average around 750,000 acres (fig. 6) . It is still one of the leading honey plants of the state. The San Joaquin and Imperial valleys give most of the honey, where it may be of light am- ber or amber color, while in Modoc County and at certain other higher elevations it is water white. The nature of the soil, as well as the condition of soil moisture and the character of growth, affects the honey crop from alfalfa. The honey is of excellent body, and readily granulates into a fine-grained solid. Larger honey crops are secured from alfalfa during dry years. While an appreciable supply of whitish-yellow pollen occurs in the bloom, bees, in most areas, secure but little of it, possibly because of the structure of the flower. Thrips are often found living inside the blossoms of alfalfa and when several are present but little, if any, nectar is to be seen. These insects apparently feed upon the nectar as it is secreted and undoubtedly re- duce nectar production by the physical injuries they cause through feeding on the plant tissues. The alfalfa butterfly frequently becomes numerous enough to mate- rially deplete the supply of nectar in alfalfa. Likewise, the alfalfa weevil tends to reduce the supply of nectar through its destruction to the plants and especially because of the cultural and control methods made neces- sary by its depredations. 13 As a rule the notes on the colors of pollen refer to the color of the pollen pellets on the legs of bees. The shade of the coloring in such quantity is frequently different from that of the pollen on the anthers; for example, in Ladino clover the anther- borne pollen looks yellow but appears brown in the bee load. 20 University of California — Experiment Station Alsike Clover. — Trifolium hybridum occurs in mountain meadows and along irrigation ditches at the lower altitudes. It yields honey that is white to extra-light amber in color and of excellent flavor. It is a good producer of dark-gray pollen. Amsinckia. — This plant is becoming abundant everywhere. It springs up quickly with warm weather, blossoming in March and April. Bees visit the yellow or orange blossoms freely for nectar and the .steady honey Fig. 5 Fig. 4. — Fireweed, Epilobium angustifolium. Compare with figure 5. For distribution see figure 33. Fig. 5. — AmsincMa lycopsoides. Often referred to as fireweed by grain harvesters. Compare with figure 4. gain at this time is partly from this source. The plant is locally referred to as fireweed, leather breeches, or woolly breeches, because the sharp plant hairs work through the clothing to cause a burning sensation ; but it should not be confused with the better-known fireweed or willow herb, Epilobium angustifolium. (Compare figs. 4 and 5.) Arrow-weed. — Pluchea sericea is a common native in the Imperial and Coachella valleys and elsewhere. The pink flowers yield a light am- ber honey of good quality. It is also known as mock willow. Asparagus. — The garden asparagus is an important source of light honey over a long season in summer. The delta region of the Sacramento and San Joaquin rivers affords surplus honey from this source. The mar- ket price of asparagus honey is in line with other honeys of the baking grade. Asparagus provides a liberal quantity of pink-colored pollen. Bul. 517] Nectar and Pollen Plants op California 21 Asters. — Many species of Aster occur sparingly over the state (fig. 7) . Bees visit them for yellow-colored pollen and nectar often after almost everything else has ceased blossoming in the fall. The California market is unfamiliar with aster honey which means probably that little of it is made. The Mexican devil- weed, A. spinosus, also called wild asparagus, Fig. 6 Fig. 7 Fig. 6. — Distribution of alfalfa, Medicago sativa. Fig. 7. — Aster (wild) of Sacramento Valley. is abundant along ditchbanks, roadsides, and other waste places in the Imperial Valley. It has a very long blossoming season and is visited by bees for the nectar and pollen. Avocado. — Avocado trees are visited by bees for nectar and pollen, and produce a surplus of dark-amber honey of strong flavor. Bees are encouraged about the groves because a pollination problem exists. It is fortunate, from the production standpoint, that there is a heavy bee population in southern California where these rich subtropical fruits are now planted so extensively. Azalea. — The species of the genus Azalea are spottedly abundant. Most of them are not in beekeeping sections and bees visit them freely for nectar over a short period only. 22 University of California — Experiment Station Barberry. — Plants of the Berberis genus are stiff, evergreen, prickly- leaved yellow-blossomed shrubs, widely distributed in foothills and mountains. They are of value to bees for pollen and nectar. Mountain grape, B. Aquifolium, occurs in northeast ranges from Napa County to Humboldt County, and in the Sierra Nevada from Amador County to Modoc County, where it produces both nectar and pollen. Basswood. — Species of Tilia are occasionally planted for shade trees in California and are heavy yielders of nectar. Bees work the blossoms Fig. 8. — Basswood or linden, Tilia americana. from daylight to dark (fig. 8). Basswood honey is water white and of nongranulating character. Beekeepers could well afford to further en- courage the planting of this excellent honey yielder as a shade tree. The tree is sometimes locally known as linden, linwood, or whitewood. Blackbrush. — Coleogyne ramosissima, often known as bitterbrush, is reported on the Colorado and Mojave deserts to be alive with bees during its blossoming period in early summer. This plant is a close relative of the antelope brush, Purshia tridentata, which also is known in certain counties as bitterbrush, buckbrush, or greasewood and is found east of the Sierra Nevada from Tulare County northward. Black Locust. — Bees gather nectar from black locust freely for about three weeks. The honey is white and of excellent flavor. Instances of ap- parent injury to bees from its nectar have been reported. It is not an important pollen source. The tree is also called false acacia. Bul. 517] Nectar and Pollen Plants of California 23 Black Sage. — This species is variously referred to also as button sage, ball sage, or blue sage. It grows 2 to 6 feet high, from perennial roots. It is one of the chief honey plants of the Pacific Coast (figs. 9 and 10). This plant, with the other sages (figs. 28, 49, 50, 59, and 60), early gave California her reputation for fine honey. The sages apparently yield Fig. 10 Fig. 9 Fig. 9. — Black sage, Salvia mellifera. Fig. 10. — Distribution of black sage. best with copious rainfall in midwinter after a period of drought. The honey is of a nongranulating type. Bees, working the sages for nectar, become covered, especially anteriorly, with a bluish-white pollen. Such individuals are conspicuous among the returning bees and are called "sage-heads" by beekeepers. Blue Curls. — Other names for this species are camphor weed, vinegar weed, fleaweed, mustang, and niggerweed. The plant (fig. 11) grows rapidly during the heat of late summer on the drier soils over much of the valley and foothill land of California and northward into Oregon (fig. 12) . It produces as much as 100 pounds to the colony in some years 24 University of California — Experiment Station at certain locations. The white honey granulates very quickly with a fine-grained texture. The pollen is green in color. Turpentine weed (Trichostema laxum), another species of the same genus, is also visited freely by bees for nectar (fig. 13) . Box Elder. — Box elder, one of the maples found along stream beds in the foothills, is freely visited by bees, especially for pollen. Two related species, the Sierra maple, Acer glabrum, and vine maple, A. circinatum, yield nectar abundantly. The latter becomes increasingly abundant northward to constitute a very important source of honey in Oregon. Eroom Weed. — See "Lepidospartum" Fig. 11 Fig. 11. — Blue curls. Fig. 12. — Distribution of blue curls Fig. 12 Buckhorn Plantain. — English plantain and ribwort are other names for this troublesome weed in lawns and pastures. Bees obtain much whitish pollen and possibly some nectar from the blossoms. The broad- leaved or common plantain, Plantago major, is not very attractive to bees. Buckwheats. — The species of wild buckwheat, Eriogonum fascicula- tum, is referred to as "flat tops" in southern California and is undoubt- edly one of the most important of the group. Although a very erratic yielder of nectar, it is the principal honey-producing plant for many southern California apiaries (fig. 14). The wild buckwheats in warm protected places on the coastal side and generally on the inland side of the ranges are excellent for nectar secretion when moisture is sufficient. In the Palmdale district buckwheat comb honey is produced. Every part of the state has certain species of Eriogonum (fig. 15) which contribute to the total honey crop. The honey has enough brown color to darken the water- white sage honey, if present even in small quantity. The color of the pollen varies with the species; "flat top" yields a brownish-colored Bul. 517] Nectar and Pollen Plants of California 25 supply. The wild buckwheats should not be confused with the cultivated varieties. Buffalo Berry. — This is a stout, spiny shrub found east of the Sierra Nevada, constituting an important source of nectar and pollen in spring. It grows along stream beds in dense thickets. Bur Clover. — This pasture plant is sometimes mentioned as a source of surplus honey but is only of stimulative value in most locations. At Davis, bees work its blossoms freely for nectar after a wet winter. Fig. 13. — Turpentine weed, Trichostema laxum. Often confused with blue curls. Burnet.- — Species of the genus Sanguisorba are forage plants with small, dioecious flowers crowded in a dense head or spike at the top of a long naked peduncle. They have rapid spring growth and bloom in late spring. The plants are drought-resistant and adapted to foothill situa- tions in coastal ranges, producing pollen abundantly, but no nectar. Button-willow. — The button-willow (not a true willow) is a small tree or bush, occurring along stream beds everywhere up to 4,000 feet alti- tude. Bees store honey rapidly from the ball-like blossoms (fig. 16) ; in the delta region, surplus honey is not unusual. It is a reliable source of both nectar and pollen since (by its location) it is abundantly supplied 26 University of California — Experiment Station with moisture and is easily "worked" by bees. In some localities the plant is known by the names button-ball bush and pond dogwood. Cactus. — Many species of the family Cactaceae, represented by such common names as Indian fig and prickly pear, occur in the state and afford some pasturage for bees, furnishing both pollen and nectar. The cacti are of particular importance under drought conditions. The honey is reported to be of light amber color and of strong flavor. Fig. 14 Fig. 15 Fig. 14. — Distribution of a wild buckwheat, Eriogonum fasciculatum. Fig. 15. — Eriogonum parvifolium, a species of wild buckwheat. California Buckeye. — The California buckeye, Aesculus calif ornica, occurs in a rim about the great valley of California from sea level to 4,000 feet or more elevation (figs. 17 and 18), often in pure stands locally. It is abundant in parts of Solano, Santa Cruz, Butte, Amador, El Do- rado, Sonoma, Tulare, and other counties. Young brood of bees fed on buckeye pollen frequently become so deformed as adults as to be unable to either walk or fly (fig. 19) . The poisonous results of this plant are seri- ous in many spots, particularly inland, when moisture for the annual plants is deficient. The honey has a pronounced odor and flavor and quickly darkens with age and light exposure; it is of nongranulating character. The pollen, as freshly collected by the bees, is reddish orange in color. See also the discussion on plants injurious to bees. California Honey Plant. — Scrophularia calif ornica is also known as figwort (fig. 20) . It is a heavy yielder of a water-white, bland honey. The plant is moisture-loving and is found mostly in partial shade. Simpson's honey plant, 8. nodosa var. marilandica, is very similar to this species. There are yellow-blossomed shrubs of this genus in the southern part of the state which yield much nectar and some yellow pollen; they are re- Bul. 517] Nectar and Pollen Plants of California 27 ported as important in Riverside and San Diego counties. Apparently bees do not collect pollen from the small-flowered Scrophularia. California Laurel. — This is an odorous evergreen tree of wide distri- bution in California, and is known by many names including bay laurel, bay tree, Oregon myrtle, pepperwood, spice tree, and simply laurel. It occurs particularly along streams and in gulches on hillsides. Bees visit the blossoms freely and secure nectar and large loads of yellow pollen during warm days of winter and early spring. Fig. 16. — Button-willow, Cephalanthus occidentalis. Camass. — Plants of the genus Camassia are widely distributed, grow- ing in wet flats and meadows in the Sierra Nevada, at 4,500 to 6,500 feet elevation, and in high north-coast ranges. Like other members of the family, it is a bulbous plant and blossoms freely in late spring or sum- mer according to the elevation. Bees visit the white or blue flowers freely for nectar and pollen. Cantaloupe. — The cantaloupe yields an abundance of nectar and pollen. The plants are monoecious, that is, male and female blossoms are separate but on the same plants (figs. 21 and 22). The blossoms, therefore, require the attention of bees and other insects for proper pollination. Some nectar and pollen are also obtained from other mem- bers of the cucurbit group, such as gourd, squash, watermelon, musk- melon, pumpkin, cucumber, and manroot. Carpet Grass. — Where sufficient moisture is available, the blossoming 28 University of California — Experiment Station of the various species of Lippia continues over a long period. The species L. repens is becoming abundant about cities. The lippias yield an abun- dance of nectar in California; the honey is excellent and of characteris- tic flavor. Other synonyms for carpet grass are mat grass, fig fruit, and lawn plant. Carrot. — Carrot occurs widely as an escaped weed and is grown for seed about Stockton, San Jose, Santa Rosa, and elsewhere. It yields nectar freely in early summer. The honey is dark in color and strong in flavor. Cascara Sagrada. — Bhamnus Purshiana is a deciduous species occur- ring in northern California and on northward as a small tree. The berries Fig. 17. — California buckeye, Aesculus calif ornica. Beekeepers suffer heavy losses from buckeye poisoning. are black when ripe. The leaves are 2% to 8 inches long. Other common names are bearberry, chittam wood, and wahoo. It is important for nec- tar in Oregon and Washington, but too rare in California to yield much. The honey is amber in color, of excellent flavor, and slightly cathartic. In California, "cascara honey" is produced primarily from Bhamnus calif ornica, or coffeeberry (p. 31), rather than from B. Purshiana. B. rubra also secretes nectar in the high Sierra Nevada. Castor Bean. — The garden castor bean provides nectar collected from extrafl oral nectaries and a small amount of pollen ; but the number of plants is insufficient to be of much importance. Catalpa. — The blossoms of these beautiful trees are attractive to bees for nectar. Catclaw. — See "Acacia." Catnip. — The garden catnip or catmint, Nepeta Cataria, is compara- tively rare in California. It is eagerly visited by bees for nectar. Were it abundant enough, no doubt this would be an important source of Bul. 517] Nectar and Pollen Plants of California 29 honey. Another species of Nepeta is reported at Berkeley to "swarm with bees." No bees have been observed working this plant for pollen. Cedar. — Incense cedar, Libocedrus decurrcns, is one of the principal sources of honeydew in California (figs. 23 and 24), the insect involved being Xylococculus macro car pae (Coleman). The honey clew varies in color from dark to light, is very heavy-bodied, resinous, and non granu- lating in character. Bees start gathering this honeydew in July and continue until late fall, the major flow coming in the fall. The yield can Fig. 18 Fig. 19 Fig. 18. — Distribution of California buckeye. Fig. 19. — Newly emerged "buckeyed" bees. Something in the California buck- eye nectar, pollen, or sap causes the death or deformity of young bees. be described as a slow flow, especially during the early period. The yield fluctuates greatly from year to year. Small waxlike particles of the scale insect adhere to the body of the bee and frequently are found in the cells of the comb in which the honey dew is stored. Chamise. — The species Adenostoma fasciculatum is also known as greasewood. It is the most abundant and characteristic bush of the coast ranges and the lower Sierra Nevada (fig. 25). It is reported to be fre- quented by bees in many places, especially for pollen. Acres of this plant in full blossom have been observed with scarcely a bee on it from hun- dreds of colonies in the vicinity. A. sparsifolium, ribbon-wood, is found at high altitudes in the mountains of San Jacinto to San Diego County. It is valuable for pollen. Chaparral Broom. — Baccharis pilularis, most often known as chapar- ral broom, also has other common names, including coyote brush, bac- charis, and water motor. It occurs throughout California west of the Sierra Nevada up to 1,500 feet elevation and yields nectar and pollen. 30 University of California — Experiment Station Several species of the genus, including B. viminea (guatemote or mule fat, fig. 26), B. glutinosa (water-wally), and B. sergiloides (squaw waterweed), are known locally to be of some importance to bees. Some of the species blossom too early in spring for bees to work them well. Chickweed. — The ten or more species of chickweed occur throughout the state (fig. 27). They are in greatest abundance during winter and early spring. In many localities they afford the earliest supply of nectar, Fig. 20 Fig. 21 Fig. 20. — California honey plant, Scrophularia calif ornica. Fig. 21. — Distribution of cantaloupe. but on account of the season are of importance to the bees for stimulative purposes only. It is also an early source of pollen from which bees secure characteristically small loads. Chicory. — The common chicory is becoming increasingly abundant. Its beautiful blossoms open in the evening, remaining well into the morning or through the day in reduced light. Bees work these plants freely for both pollen and nectar. The plant is also known as blueweed. Chinquapin. — The chinquapin is a shrub or small tree occurring in the high mountains of southern California and the Sierra Nevada, at 3,000 to 8,000 feet, where it furnishes pollen and an amber-colored honey. In the coast ranges it occurs at 1,500 to 4,000 feet elevation. Christmasberry. — See "Toyon." Citrus Fruits. — See "Orange." Cleome. — Cleome serrulata, or Rocky Mountain bee plant, is a superb honey source in many places from Colorado westward. This species is rare, however, in California, being reported from Point Sur, San Diego, and a few other places. The closely related species, C. lutea, is found Bul. 517] Nectar and Pollen Plants of California 31 in the desert region of Inyo and Mono counties where it is much visited by bees during summer. Nectar from this species has a lower sugar con- centration than either alfalfa or sweet clover and therefore this plant is frequently neglected by the bees when the other two are in bloom. Clotbur. — During late summer, bees visit the small blossoms of this plant eagerly for nectar. It has not been found in sufficient abundance to be spoken of as important, but indications are that it has possibilities. Fig. 22. — Cantaloupe, Cucumis melo. Pollen must be transferred from the staminate blossom (a) to the pistillate (b). It is also called spiny cocklebur or Spanish thistle. The common cockle- bur, Xanthium canadense, is listed as a source of pollen and possibly honey, which is presumed to be honeydew. Coffeeberry. — This is a very important plant along and below the San Francisco Bay region, in the Sierra Nevada foothills, and elsewhere. It grows in thickets and is an evergreen shrub with globose berries, black when ripe and about % inch in diameter. The leaves are 1% to 2% inches in length. The plant, although easily distinguished from the deciduous cascara sagrada, is often confused with it. The honey is reported to vary from white to amber in color. It is of good flavor, and slightly cathartic. In some localities the plant is also known as buckthorn. Composites. — This is an extremely large group of plants, both wild and cultivated, widely distributed throughout the state and in the aggre- 32 University of California — Experiment Station gate provide a major source of pollen and much nectar. Only a few of the more important species are discussed under dandelion, star thistle, tarweed, sunflower, and asters. Corn and Sorghum. — A great abundance of pollen is gathered from corn plants annually. As many as 20 bees have been observed gathering pollen from one tassel of Zea Mays. An observer at Dixon reported a crop of honey from Egyptian corn one season. Probably most of the Fig. 23 Fig. 24 Fig. 23. Distribution of incense cedar. Fig. 24. — A section of a twig from incense cedar with hanging drops of honeydew. This sweet exudate frequently drips from the trees in late autumn. "nectar" thus gathered is honeydew, of either insect or plant origin. Milo furnishes a good source of pollen in the Sacramento Valley during late summer. Cotoneaster. — These plants appear to be an important minor source of nectar, secreting freely throughout the day. Honeybees prefer this nectar to such an extent as to ignore other plants when cotoneaster is in bloom. The pollen as collected by the bees is of a greenish-gray color. Cotton. — The common field cotton is a very important source of nectar in only part of the areas where grown. It yields well on the old lake soils in Kern County, giving a surplus of good light-colored honey. The re- placement of alfalfa with cotton results in a reduction of nectar for the beekeeper. Cotton has both floral and extrafloral nectaries. In parts of the Old South, cotton is the leading honey plant. The cotton honey gran- ulates quickly and forms hard crystals. Cotton pollen is pale yellow in color. Bul. 517] Nectar and Pollen Plants of California 33 Cotton Thorn. — This bush occurs extensively in the desert region of the eastern part of the state and is particularly abundant in parts of Inyo and Mono counties. It blossoms in May and is reported to afford a liberal supply of nectar. The name lemon sage is also applied to this species. Fig. 25 Fig. 2( Fig. 25. — Chamise, Adenostema fasciculatum. (Courtesy, F. C. Pellett.) Fig. 26. — Chaparral broom, guatemote, or mule fat, Baccharis viminea. (Courtesy, F. C. Pellett.) Cottonwood. — These familiar trees afford an important supply of pollen during early spring. Coyote Mint. — This mint is abundant over a wide range in elevation in the Sierra Nevada where it is of considerable importance as a source of honey. Creeping Sage. — This low-growing sage occurs in dense stands in numerous, widely scattered localities on the western slopes of the Sierra Nevada and elsewhere from 1,000 to 4,000 feet elevation (fig. 28). It is often found in isolated patches, particularly at the edges of chamise thickets. While it is an erratic source of nectar, available records show 34 University of California — Experiment Station that it occasionally provides large crops of honey. The quality of the honey is equal to the black sage honey of the southern coast region. After a fire which burns off the chamise and other cover, this plant is likely to give a surplus honey crop for two years (see also "Sage"). Creosote Bush. — This evergreen bush (fig. 29) is abundant in areas of the Mojave and Colorado deserts, where it is often spoken of as an important secondary source of nectar. It is sometimes called greasewood on account of the sticky foliage. It produces pollen abundantly. CbscA Weed $ie7lar*i<2, media Fig. 27 Fig. 28 Fig. 27. — Common chickweed. Fig. 28. — Distribution of creeping sage. Dalea. — The various species of Parosela are common in the desert of southeastern California, and northward into Nevada as far at least as Reno where they are commonly referred to as "purple sage." The low- growing, purple-blossom species of Inyo and Mono counties are very attractive to bees for nectar. The smoke tree, P. spinosa, also affords some nectar. The honey is light in color and of excellent flavor. Dandelion. — The different dandelions are not so important in Cali- fornia as is the case in the humid eastern United States. The common dandelion (naturalized from Europe) is widely scattered now in lawns and moist meadows, being an ever present source of some nectar and much orange-colored pollen. Several species of the genus Agosaris, commonly called sea dandelions, are abundant along the coast where bees visit them freely for both pollen and nectar. Bul. 517] Nectar and Pollen Plants of California 35 Death Camas. — A number of species of the genus Zygadenus produce nectar and pollen which bees collect. Z. venenosus is reported at times to be injurious to the honeybee. Fig. 29. — Creosote bush, Larrea tridentata. Deciduous Fruits. — Most of the deciduous fruits are of but secondary importance for honey. The fruits blossom so early, before the bees are well built up from winter, that special attention is necessary to procure a crop of honey. An average of 25 pounds of surplus honey from apple and prune has been secured in Sonoma County in favorable years. Apple 36 University of California — Experiment Station honey is good in flavor and color, while plum and prune honey is often of inferior flavor and color. Almond honey is light in color and very bitter in flavor. Peach, apricot, and pear yield some nectar. Some cher- ries yield a good supply of nectar as well as pollen. Pear is reported to be of importance for honey in parts of the United States, but in Cali- fornia bees prefer to collect the more concentrated nectar of other plants. All deciduous fruit blossoms provide copious sources of pollen. The pol- len varies with the source from pale yellow to dark brown. Desert Peach. — This is fairly abundant east of the Sierra Nevada, where it is important, particularly for pollen, during the brood-rearing period of spring. Other species of the genus Prunus (western choke- cherry, bitter cherry, and Sierra plum) are a source of considerable nectar in the mountains over a wide area. Dodder. — This leafless, yellow-colored parasitic plant, often called love vine, is becoming common on many hill ranges, particularly in southern California. The small blossoms of dodder yield nectar freely during summer and fall. Reports from Texas and elsewhere indicate that bees are poisoned by dodder if they feed on it to excess. 14 Elderberry. — Various species of elderberry are widely distributed along streams in California and constitute a minor source of straw- yellow pollen during the summer months. Elm. — In many sections of California the European elms provide an important source of grayish-yellow pollen on warm days in early spring. Much insect honey dew occurs on these trees in late summer and fall, but is seldom attractive to bees. Eucalyptus. — Members of the large Eucalyptus genus comprise an important source of honey in their native land (Australia) and certain of them are now valuable bee plants in this state. The blue gum, E. globu- lus (fig. 30), has been extensively planted about the San Francisco Bay region and in southern California where it yields honey abundantly. The blossoming period is in late winter and early spring when the weather is not always suitable for the gathering of nectar. In addition, the plants do not blossom heavily every year. The blue gum around Oak- land produces a heavy crop of honey one year in four. Red gum (E. ros- trata) is planted rather extensively in the hot interior valleys where considerable honey is stored from it each year. Many other species should be mentioned as sources of honey, including manna gum, E. viminalis; desert gum (fig. 31) , J57. rudis; white ironbark, E. leucoxylon; mahogany gum, E. robusta; forest gray gum, E. tereticornis; and scarlet bloom, E. ficifolia. The honey from these trees in California is rather pro- nounced in flavor, especially when a slow nectar flow is experienced. All 14 Parks, H. B. Dodder. Beekeeper's Item. 14:492-93. 1930. Bul. 517] Nectar and Pollen Plants of California 37 species of Eucalyptus so far studied yield nectars of relatively low sugar concentrations. The white pollen is collected by bees only in moderate quantity. False Indigo. — This is a deciduous shrub 3 to 7 feet tall with heavy- scented herbage. This species is found along streams in the foothills and mountains on south slopes of San Gabriel and San Bernardino moun- tains to San Diego County. It is reported of value for nectar and pollen. Fig. 30 Fig. 30. — Blue gum, Eucalyptus globulus. Fig. 31. — Desert gum, Eucalyptus rudis. Fig. 31 Fennel. — This plant, commonly called sweet fennel, has a strong aro- matic odor, resembling anise oil. It is widely scattered and often abun- dant in waste places. Bees visit the blossoms eagerly for nectar. Figwort. — See "California honey plant." Filaree. — The white-stem filaree, Er odium moschatum (fig. 32), is a well-known stock forage plant with numerous common names, among which are alfilaree, pin clover, scissor weed, musk clover, pin grass, heron's bill, and stork's bill. It is a member of the geranium family and from it, as from very many others of the group, considerable nectar and pollen are gathered by the bees. In northern California, at least, this is visited mostly during early morning, since the blossoms open at night and but few remain open during the day except when the weather is cloudy. Beekeepers have reported a surplus from this source, but as a rule, stimulation of the bees to more activity is the chief benefit to the apiary. Red filaree, E. cicutarium, yields a bright-red pollen which soon 38 University of California — Experiment Station fades in the combs to brownish yellow. The honey is extra-light amber to white. Fir.— See "Pine." Fireweed. — This is a perennial herb (fig. 4), occurring in far north- ern California and at high altitudes southward (fig. 33). It is called buckweed in Mendocino County. The chief honey plant to the north of California along the coast and in the Cascade Mountains, it is a moisture- loving plant and is particularly abundant for a period after forest fires, when it occasionally yields a heavy crop of excellent honey. The pollen is commonly blue in color. (See "Amsinckia.") Fig. 32.— Filaree. Flax. — The cultivation of flax for seed in California has increased greatly during the past few years; in 1939, over 100,000 acres were de- voted to this crop. The blue blossoms shatter from the plants early in the day but while present are freely visited by bees for both pollen and nectar. The pollen is blue in color and the honey is water white. Forest Clover. — This legume constitutes an important source of honey and pollen in open forests at 3,000 to 6,500 feet in the Sierra Nevada from Mariposa County to Plumas and Butte counties, thence westerly to Trinity County. The honey is white in color. Garden Flowers. — Generally speaking, garden flowers are of little importance for bees on account, in part, of their limited number; also, many of them have blossoms of such a structure that the nectar supply is not within the reach of a bee's tongue (see "Honeysuckle"). With large-area plantings, as in the case of seed production, bees may obtain an appreciable supply of nectar from certain species. In the aggregate they contribute to the pollen supply of the colony. Gilia. — Many of the gilias are important local sources of nectar and pollen in May and June; two species, one tall and one dwarf, have Bul. 517] Nectar and Pollen Plants of California 39 yielded as much as 50 pounds surplus in the Butte Flat vicinity. The pollen is commonly blue in color. Globe Artichoke. — The large, blue blossoms of these plants are very attractive to bees for pollen and nectar during May and June. Many dead bees have been observed upon the artichoke blossoms by independ- ent observers. The factor causing the death of the bees is still unknown. Golden Fleece. — The species, Ericameria arhorescens, is an important source of pollen and nectar in fall in the coast ranges from Napa County to Monterey County and south to Santa Barbara County; also in the Sierra Nevada from El Dorado County to Tulare County. The honey is amber in color. Goldenrod. — Goldenrod occurs widely in the hill country of Cali- fornia, and is visited by bees for pollen and nectar. Solidago occiden- talis is of considerable value for honey at Placerville, but generally goldenrod is not numerous enough to be important. Grape. — The blossoms of the cultivated grape are sometimes attrac- tive to bees for pollen. The more fragrant California wild grape blossoms provide both pollen and nectar and are more attractive than the culti- vated varieties. Grasses. — Many of the grasses, other than corn, such as Sudan, Ber- muda, and Johnson grasses, furnish considerable light-yellow pollen, throughout the summer months. (See also "Corn.") Hazelnut. — Both the hazels and filberts bloom during the winter and early spring and provide an abundant supply of early pollen, which the bees gather when the weather permits. The pollen is of various shades of yellow. These species occur naturally along streams in cool canyons and on moist slopes. The filberts are being grown in increasing quantity for commercial purposes. Heather. — The heathers, both Scotch (fig. 34) and Mediterranean, are becoming common in landscaped areas. These blossom profusely in early spring when bees may be unable to fly freely. The famous dark- colored heather honey of Europe is from these and similar species. There are some native heathers in the high Sierra Nevada where few, if any, hive bees exist. Hemp. — Hemp cannot be grown legally in California, but it occurs as a weed in many places. Bees collect a great deal of pollen from the blossoms during summer. Colorado River hemp, Sesbania macrocarpa, a legume, which grows in the Imperial Valley region, is freely visited by bees for nectar. Hoary Cress. — These pernicious weeds are now established in various places in California. The flowering branches bear numerous showy, small white flowers and are freely visited by bees for nectar and pollen. 40 University of California — Experiment Station Hollyberry. — This beautiful evergreen, Bhamnus crocea, is bushy in nature of growth. The plant should not be confused with the Christmas- berry or toy on. Its leaves are small and prickly; bees work it freely for nectar over its entire range. It is commonly called redberry. Honeydew. — The main source of the sugars that bees get is nectar from flowers. Other sources which should be mentioned, however, occur Fig. 33 Fig. 34 Fig. 33. — Distribution of fireweed, Epilobium angustifolium. Fig. 34. — Scotch heather, Erica melanthera. more frequently than is recognized by beekeepers. The name "honey- dew" is applied to the sweet exudate of many groups of insects such as aphids, leafhoppers, scales, and gall insects, as well as that from certain plant tissues. It is eagerly collected in many instances by the bees, espe- cially when floral nectar is not available. As a rule, the color of honeydew is very dark (some exceptions) and of pronounced flavor. Where the bees are confined long by cold, digestive disturbances may occur from the consumption of such "honey." In the Sacramento Valley, and imme- diately around it, the gall insect, Disholcaspis eldoradensis, sometimes Bul. 517] Nectar and Pollen Plants of California 41 affords an extraction of honeydew from the oak. As much as 30 pounds per colony of oak honeydew honey has been reported for the vicinity of Cottonwood. Indian honey and manna are local names for honeydew honey. Honeydews, as a rule, are produced long after the plants are in bloom and therefore contain no pollen from the host plant. Honeysuckle. — Most of the honeysuckles produce nectar in abun- dance but it is ordinarily not within reach of the bee's tongue (fig. 35). Often, however, the nectar hangs in drops from an inverted blossom (canyons of southern California) where it appears to be unattractive to bees while the sages are in blossom. Some of the dwarf species in the hills annually contribute somewhat to the honey crop from miscellaneous sources. Hop. — Hops are grown extensively in river bottoms, particularly along the Sacramento, and are mentioned occasionally as a minor source of pollen. In commercial plantings very few male plants are used and this increases the importance of the honeybee as a pollinating insect. Horehound. — This plant is scattered widely in California and is par- ticularly abundant in parts of Napa County. In spite of the dark, ill- tasting honey, this plant is beneficial to Sacramento Valley beekeepers since it blossoms during the severe summer dearth period experienced there from May to July. Bees appear to prefer this plant (fig. 36) over many others, perhaps on account of the easily available or rich nectar. The honey is too strong for table use but finds a place in medicines, cook- ies, and candies. It is looked on with disfavor by beekeepers in scattered areas in the sage ranges because only a small amount of its honey will reduce the quality of honey secured from the sages. Hound's Tongue. — The beautiful blue-flowered blossoms of the genus Cynoglossum are attractive to bees for nectar. C. grande occurs in wooded canyons up to 4,000 feet while C. occidentale is found in moist thickets and woods of mountain slopes and flats between 4,000 and 7,000 feet elevation. Hypochoeris. — These plants are visited by bees for both pollen and nectar over a long season in summer. They are commonly called cat's- ears. In Oregon, Hypochoeris radicata is known as California or fall dandelion and is considered a fine pollen plant. Ice Plant. — This plant occurs along the coast and on the adjacent islands from Santa Barbara to San Diego counties, being abundant in areas. It is commonly called sea fig and sea marigold. Bees gather nectar freely from it. The honey granulates almost as fast as made. Other spe- cies of the genus are commonly used for wall cover in gardens. Bees eagerly visit the blossoms for nectar and pollen, but the plants are prob- ably not numerous enough to be of much importance. 42 University of California — Experiment Station Incense Cedar. — See "Cedar." Jacaranda. — Jacaranda ovalifolia is a tree with beautiful purple blos- soms and is planted in southern California as a shade tree. Bees work it freely for nectar and pollen in May and June. Jackass Clover. — This legume, Wislizenia refract a, is a valuable ad- dition to the nectar sources of the San Joaquin Valley where it yields Fig. 35 Fig. 36 Fig. 35. — Honeysuckle, Lonicera sp. The corolla tube length exceeds that of the bee's tongue. Fig. 36. — Horehound, Marrubium vulgare. Compare with black sage in figure 9. a large quantity of good honey on alkali plains, mainly on spots not cov- ered by alkali. It yields best where there is water about 3 feet below the surface but also does well on soils too dry for most plants. Since it is confined to nonagricultural lands, systematic scattering of the seed could be encouraged. A correspondent at Selma reports excellent honey crops from this source. It yields in alternate years, at least in some localities. This plant has been recently reported from Arizona where it is a heavy yielder. It also occurs over much of southwestern Nevada, but little is known of its value there. Small loads of gummy, brownish-colored pollen are gathered by bees, as well as the excellent quality of nectar. It is locally known as stinkweed. Bul. 517] Nectar and Pollen Plants of California 43 Klamath Weed. — The number of stamens in these plants is large and each provides a visible supply of pollen. Keported to be a heavy yielder of pollen in Sonoma County, klamath weed, or St. Johnswort {Hyperi- cum perforatum), is a source of bright-yellow pollen for the bees over a wide area in northern California. Several cultivated species are also visited freely for pollen. Koelreuteria. — This medium-sized tree blossoms in July, at Davis, where it is also known as "varnish tree." Bees work the yellow blossoms heavily for nectar. There are comparatively few trees available, al- though its use as an ornamental is increasing. The seeds are hard and black, enclosed in a conspicuous bladderlike capsule. This is not to be confused with the umbrella tree, Melia Azedarach, nor with the tree of heaven, Ailanthus glandulosa. Ladino Clover.— See "White Clover." Lepidospartum. — This yellow-blossomed perennial affords nectar and golden-yellow sticky pollen during summer and fall in southern Cali- fornia. It occurs on sandy washes and gravelly plains and is also known as burrow weed and broom weed. Lily. — Many members of the lily family are visited by bees for both nectar and pollen. Certain tulips, in particular, produce a black pollen. Lima Bean. — The lima bean acreage of California is large. In general, most of the beans are of secondary value for honey production; the one exception is the lima. The baby lima yields nectar abundantly when con- ditions are suitable. Cool weather seems to be essential to its best growth. Along the southern coastal plains, where most of the baby limas are grown (fig. 37) , bees are moved within reach every year. In Yolo County, and other inland localities, the lima bean may or may not secrete suffi- cient nectar to be stored by bees. Lima bean honey is of delicious flavor and heavy body; it granulates readily and is of fine texture. The lima bean provides little if any pollen for the bees. The black-eye beans are reported to give some honey of near-amber color. Lippia.— See "Carpet Grass." Locoweed. — The several species of the genus Astragalus occur com- monly throughout California and are visited frequently by bees for both pollen and nectar. A. lentiginosus produces a reddish-colored pollen. There is evidence that this species is detrimental to bees, causing paraly- sis and death, generally in the field. Kecent investigations have shown that under certain soil conditions, selenium accumulates in plants to such an extent as to be poisonous to animals. There is a possibility that this substance may be the causative factor in the nectar of the species A. lentiginosus. 44 University of California — Experiment Station Loquat. — The blossoms of the loquat produce pollen and nectar abun- dantly during winter. Many honeybees and other insects come to the trees during the sunny hours. Lupines. — Apparently most of the lupines are not very attractive to bees. Keports are sometimes received crediting lupines as the source of a crop of honey, but some doubt is entertained concerning their reliabil- ity. Certain species supply a brownish-red pollen for the bees. Fig. 37 Fig. 38 Fig. 37. — Distribution of lima bean, Phaseolus sp. Fig. 38. — Madrone, Arbutus MeTwiesii. Madrone. — This rather striking tree is reported of value for honey in the Sierra Nevada foothills and from Santa Cruz County northward along the coast into Oregon. Its blossoms (fig. 38) much resemble those of manzanita (fig. 39). The honey is said to be of excellent quality. The sugar concentration of the nectar is low and numerous observations have revealed that but few honeybees visit the blossoms when other plants are available, as for example, manzanita and apple. Honeybees rarely work this plant for pollen. Manzanita. — These bushy plants occur over nearly all the hills and mountainous country up to 9,000 feet, even where moisture is scarce and in many places where the soil is too shallow to support tree growth. The blossoming period occurs during winter and early spring which often precludes the storage of much honey in spite of the great abun- dance of nectar available. The honey has a faintly bitter taste when Bul.517] Nectar and Pollen Plants of California 45 fresh; but after extraction the flavor improves. Thrips seriously injure these blossoms at times at the 5,000-foot level in El Dorado County. The juglike blossoms secrete nectar previous to maturity, a rather unusual phenomenon. Pollen gathering from the manzanita is negligible. (See fig. 39.) Fig. 39. — Parry manzanita, Arctostaphylos manzanita. (Courtesy, J. M. Goodyear.) Meadow Foam. — This and other low-growing species of Linuianthes carpet the ground on "salty" spots in early spring. Nectar is secreted abundantly, and, if the weather is suitable, bees work it heavily. Prob- 46 University of California — Experiment Station ably but few bees are within reach of the major part of its location since it grows on barren low stretches subject to winter flooding. Meadow foam, also known as marsh flower, is of considerable importance for stimulative purposes. The honey is light in color and of good flavor. Mesquite. — Mesquite occurs only in the southern part of the state (fig. 40), particularly in the hot eastern interior. It is an important source of nectar and pollen but not altogether reliable. The species g$0**^& u Fig. 40 Fig. 41 Fig. 40. — Distribution of mesquite. Fig. 41. — Details of flowering parts of two species of mes- quite : a, Prosopis juli flora; o, screw bean, P. puoescens. (Both after Jepson.) Prosopis juliflora var. glandulosa grows to tree size, with sufficient mois- ture, and is largely confined to the better soils. It is sometimes called honey locust, algaroba, keawe, honey mesquite, honey pod, and iron- wood. The flowers occur in dense spikes (fig. 41, a). The honey is well flavored, granulates readily, and forms large hard particles which are difficult to liquefy. Keawe, or a similar variety, was early introduced into Hawaii where it thrived and now it produces an immense amount of white honey for export. The screw-bean mesquite, P. pubescens, also contributes its share of nectar. The peculiar screw-bean pods are pic- tured in figure 41, b. Milk Thistle. — Silybum Marianum is an abundant plant in the Sacra- mento Valley, and constitutes an important source of purplish pollen during May. In limited areas this weed, especially during wet seasons, Bul. 517] Nectar and Pollen Plants of California 47 greatly relieves the dearth period occurring between mustard and al- falfa. It also provides some greenish-colored honey. Milkweed. — Various species of milkweeds are of wide distribution. In some eastern states milkweeds are a major source of honey, but they sel- dom occur in this state in sufficient quantity to be of value as a nectar source, although they yield freely. Bees as well as other insects are caught and held until death by the pollen-bearing parts. Fig. 42. — Mistletoe, Phoradendron flavescens. Milkwort. — This is a low-growing perennial occurring extensively in the Sierra Nevada. Milkwort yields water-white honey occasionally, as much as 30 pounds surplus being reported from above Placerville. Many species of Poly gala are found almost all over the hills of the state. Mistletoe. — The several species of mistletoe afford pollen and nectar. The blossoms are minute and greenish in color. It grows as a parasite on cottonwood, walnut, black locust, sycamore, and other trees. Phora- dendron flavescens (fig. 42) blossoms in February and March and is freely visited by bees for pollen and nectar. It is not abundant enough to be of much importance. Mojave Stinkweed. — This is a near relative of jackass clover and the Rocky Mountain bee plant and occurs in the Mojave and Colorado deserts and northward into Inyo County. It has a long blossoming period and is very attractive to bees as a source of nectar. 48 University of California— Experiment Station Morning-glory. — Bindweed or wild morning-glory is widely distrib- uted in California. The white blossoms provide a rich source of white pollen and some nectar for the bees. Mountain Grape. — See "Barberry." Mountain Misery. — This plant is known by a large number of com- mon names among them being: bear clover, bearmat, Jerusalem oak, running oak, bitterbark, kittikit, mountain tarweed, and squaw carpet. This shrub covers wide stretches of pine wood and open hillsides, from Plumas County to Kern County at 3,000 to 6,000 feet elevation (fig. 43) . Fig. 43 Fig. 44 Fig. 43. — Distribution of mountain misery. Fig. 44. — Mountain misery, Chamaebatia foliolom, a plant of low carpetlike growth. The small, white blossoms (fig. 44) and the nature of growth remind one of a great strawberry planting. Bees visit it freely for nectar and pollen. Correspondents from Tulare, Fresno, and El Dorado counties report a slow nectar flow, producing a dark honey of fair quality and quantity. The plant is a consistent bloomer and the pollen is orange red in color. Mullein. — This is a common, tall-growing weed on the coast and in- land on flats, valleys, mountain ridges, and, particularly, dry stream beds and around deserted mountain homesteads. It should not be con- fused with turkey mullein. Bees visit the yellow blossoms in late summer for nectar, but possibly it is not abundant enough to give surplus honey. It is an important source of orange-colored pollen in late summer and fall. Other species of this genus are of some importance to bees, as for example both mullein, V erbascum Blattaria. Mustard. — Several species of the genus Brassica occur commonly in various parts of the state and provide an important source of pollen Bul. 517] Nectar and Pollen Plants of California 49 and nectar in early spring. The white mustard, B. alba, grown com- mercially in Lompoc Valley, gives honey of light quality. The red or black mustard in the same locality yields a more inferior honey. (The names white, red, etc., do not apply to the blossoms, which are yellow in color.) Red-mustard honey is strongly flavored and granulates quickly, often before extraction, into coarse particles; while that from the white is mild, granulating slowly with fine texture. The black mustard of the grain fields in the Sacramento Valley fails to yield nectar some seasons, Fig. 45. — Myrtle, Myrtus communis. but occasionally a large crop of light amber to amber, rapidly granulat- ing honey is obtained. In Napa Valley, the common yellow mustard B. campestris blossoms in February and March, and produces light- colored honey annually. This species of mustard is common in many sec- tions of California, and is of considerable importance, especially early in the season. The pollens are of a light-yellow color. Myrtle. — Some of the several introduced species of the genus Myrtas — for example, M . communis, shown in figure 45' — are visited nearly throughout the year for small quantities of nectar and much pollen. Napa Thistle. — This abundant and persistent weed, also known as Lombardy star thistle and tocalote (fig. 62), is found over much of the state. It is not considered of importance for nectar generally. Bees have been observed to work it occasionally for pollen. Nightshade. — Several of the nightshades (Solanum spp.) are re- 50 University of California — Experiment Station ported to be visited by bees. Those in the Sacramento Valley seem to be avoided. Wm. G. Watkins of Placerville has evidence of bees' being poisoned when working certain species, the pollen in particular being deleterious. Oak. — There are numerous species of oak (genus Quercus) which should be mentioned in connection with pollen plants. Most of them give an abundance of pollen in the spring. Honeydew from the multitude of scale and gall-insect inhabitants of oaks is of considerable importance. Great quantities of this are stored by bees annually; in some cases the color is dark, while again, light-colored honeydew is reported. The scrub tan oak, Lithocarpus densiflora, which is associated with the red- wood, also produces considerable pollen and honeydew. Olive. — The olive is generally grown over much of California. Bees have paid but little attention to these blossoms at Davis over a period of 20 years, except for the large amount of bright-yellow or orange- colored pollen. Surplus honey has been reported only in two instances — in Riverside and Tulare counties. Onion. — The onion-seed growers incidentally produce a great quan- tity of nectar for the bees. In this state the principal source of onion nec- tar, as far as cultivation is concerned, is in the lower Sacramento and San Joaquin delta areas in Sonoma County, and in the Santa Clara and Imperial valleys (fig. 46) . There are a number of native species in moun- tain and valley which are important locally; for instance, on the lava beds in Plumas County (elevation, 5,500 feet), a pink-blossomed onion about 4 inches in height swarms with bees in May. This honey ought to enjoy a good demand among onion-loving persons. The characteristic onion flavor, however, is said not to be present when the honey is thor- oughly ripened. Orange. — The citrus fruits such as lime, grapefruit, lemon, and or- ange, produce more or less honey, but the orange leads. The honey from all citrus is of similar quality, and is sold as "orange." It carries a heavy orange-blossom odor, which is so pronounced that the mere presence of this honey on the table may fill the whole room with a delicate aroma. Several hundred carloads of this honey are produced in certain areas (fig. 47) annually and it commands a premium on the market. Good bee- keeping practices are necessary for procuring this crop, since it comes early, often before the colonies are strong enough to store surplus. The humidity is high during the production period and special attention should be given to proper ripening before extraction. Occasionally in southern California nectar is so abundant that it drops from the blos- soms at the slightest jar. The orange blossoms, as with manzanita, begin to secrete nectar before the petals unfold. The navel blossoms do not Bul. 517] Nectar and Pollen Plants of California 51 produce pollen while those of the Valencia yield a yellow-colored supply for the bees, the loads being of small to medium size. Humidity has an important bearing on honey yield; orange nectar, as secreted, has a rela- tively low sugar concentration and unless atmospheric conditions favor a high rate of evaporation of the moisture the bees are not attracted to the blossoms. Palm. — Many of the palms (Phoenix spp.) give an abundance of pollen and possibly some nectar. The staminate and pistillate blossoms are on separate trees. The date palm growers consider bees unfavorably Onion seed areas. Fig. 47. — Distribution of orange. because they carry away pollen needed in the common practice of hand- pollination. The Canary Island date palm, P. canariensis, frequently gives a large quantity of whitish pollen which is eagerly collected by the hive bee ; figure 48 pictures the pistillate and staminate blossoms of this palm. Paloverde. — The border paloverde, Cercidium Torreyanum, occurs in the dry areas of southeastern California. The yellow flowers appear in April. Bees visit the blossoms freely for nectar and pollen, although it is said that this species is not of so great importance for nectar as are the mesquites of the same region. The male paloverde, Parkinsonia micro- phyllum, grows well in the northern part of the Sacramento Valley and is visited readily by bees from early July to late summer, for a bright orange-yellow pollen and some nectar. Passionflower. — The blossoms are large and showy, and very attrac- tive to bees for nectar and pollen. Nectar is visible in the nectaries throughout the day. Pentstemon. — Several members of the genus Pentstemon secrete nec- tar freely enough to be of some value to bees. Various species occur 52 University of California — Experiment Station throughout the state. P. breviflorus is eagerly visited for nectar in Alpine County during late summer. P. antirrhinoides, along with black sage, gave a 5- to 8-pound daily increase per hive about Moreno in May, 1926. Peppertree. — The California peppertree, Schinus Molle, grows throughout southern and central California at low altitudes; it freezes back severely to the northward. During the blossoming periods, the trees are visited by bees for nectar and pollen. The honey has a hot, peppery taste. Fig. 48. — Blossoms of Phoenix canarien- sis, the Canary Island date palm. The pis- tillate flowers are shown on the left. Persimmon. — The cultivated persimmon acreage in California is about 1,570 acres. Bees visit the blossoms eagerly for nectar and pollen, but few locations have enough of the trees within reach to yield surplus honey. As with most of the other deciduous fruits, the flow is considered to be only stimulative, although in the eastern part of the United States the wild persimmon is locally considered important. Phacelia. — Some of the species of Phacelia occur almost everywhere in patches. They are an important source of nectar of good quality. Under experimental cultivation at Davis, fiddle-neck, or P. tanacetifolia, gave a small surplus of light-green honey of fine flavor, and great quan- tities of dark-blue pollen. Carloads of honey were reported from Ven- tura County from caterpillar phacelia, P. hispida, in 1908. Rock pha- celia, P. calif ornica, is a source of honey at high altitudes in the Sierra Nevada. Bul. 517] Nectar and Pollen Plants of California 53 Pine. — The name "pine" is often used by beekeepers to include the pine, fir, hemlock, and other coniferous trees from which bees gather honeydew and pollen. (See also "Cedar.") The honeydew is produced from aphids and scale insects on the firs in particular, the flow occurring earlier than that from incense cedar, which is produced entirely by a scale insect. These conifers produce pollen in abundance which, because of very light weight, bees carry in extremely large loads. The pollen from the lodge pole pine is very pale yellow in color. Pittosporum. — Members of the Pittosporum genus are used rather extensively in ornamental plantings. Some of these are hardy only along the coast. Bees visit the blossoms freely for nectar and pollen but the actual value for honey is not great. Poison Oak. — The well-known poison oak plant is widely distributed over the coast ranges and Sierra Nevada up to 5,000 feet. It is an im- portant addition to the nectar flora in many areas, particularly in the coast ranges. The honey is light in color and of good quality but granu- lates rapidly; sometimes frostlike crystals of it collect on the side of the extractor. Other species of the same genus are important as a source of amber honey in southern California and elsewhere. Pomegranate.— The bees freely visit the commonly grown pomegran- ate, for nectar and pale-yellow pollen. Poppy. — The California poppy is exceedingly abundant in spring and summer. From it bees secure orange-colored pollen, but little if any nectar. Certain cultivated poppies are reported to be somewhat injurious to the bees visiting them. A few varieties of ornamental poppies provide a pollen of black color. Potentilla. — A large number of species of Potent ilia occur in Cali- fornia, generally under the common name "five-finger." Bees visit this group for pollen and undoubtedly some nectar is also obtained. Privet. — Bees eagerly work the small white blossoms of the common hedge plant, privet, for both pollen and nectar. The blooming period extends over two or three weeks in early summer. The pollen is yellow with a greenish tint. Purple Sage. — The purple sage grows more rankly than the black sage and the plants are of a decidedly lighter color. The common name, silver sage, no doubt refers to the silvery appearance of the plants at a dis- tance. Only a few patches occur outside the area indicated in figure 49. This plant (fig. 50) is equal in producing possibilities to the black sage, but it has a much narrower distribution, being reported to only 1,500 feet elevation. Purple Star Thistle. — The purple star thistle, Centaurea calcitrapa, 54 University of California — Experiment Station occurs widely scattered about the San Francisco Bay region, inland, and northward, but is usually not abundant. This weed (fig. 62) is charac- terized by much heavier spines than the yellow star thistle. Bees visit the blossoms freely for nectar. Rabbit Brush. — Of the many species and varieties known as rabbit brush, Chrysothamnus nauseosus yields considerable honey, but of very inferior quality. The species is abundant in areas east of the high moun- tains in Alpine, Inyo, Modoc, and other counties. The light amber honey, Fig. 49 Fig. 50 Fig. 50.- Fig. 49. — Distribution of purple sage. -Purple sage, Salvia leucophylla, with a bee on a blossom. (Courtesy, E. R. Eoot.) of disagreeable taste and smell, is usually left in the hives for winter food. Luckily it comes in after the better honeys from alfalfa, sweet clover, and fireweed are harvested. Radish. — The wild form of radish is becoming an abundant weed over the state. Bees store more or less nectar from it, in the Sacramento Valley and elsewhere. Under suitable moisture conditions, it will continue to blossom throughout the summer, but the major bloom is in early spring. The pollen is a darker shade of yellow than that from common mustard. Raspberry. — Several species of Eubus are widely distributed over hill and mountain in California and all yield some nectar and pollen. The thimbleberry, found from 4,000 to 8,000 feet elevation, is of considerable importance. In the Great Lakes region, raspberries constitute a major source of nectar, and the honey is of very high quality. The blackberry belongs to this same genus but does not have the reputation of being of much value for nectar except in the mountains. Redbud. — The western redbud, or Judas tree, a large shrub, although widely distributed (up to 4,000 feet), is relatively scarce except in Bul. 517] Nectar and Pollen Plants of California 55 favored localities. It blossoms almost too early for best results for honey, but is visited freely on warm days by bees, especially bumblebees, for pollen and nectar (fig. 51) . Red Clover. — Red clover is scarce in California except in the northern mountains. It is not considered an important source of honey but does yield a dark-brown pollen. Red Maids. — Calandrinia caulescens var. Menziesii (fig. 52) , the plant known as red maids, occurs abundantly in orchards and vineyards; the Fig. 51. — Redbud, Cercis occidentalis. purplish-red blossoms frequently carpet the ground from noon to even- ing. It blossoms during March and April and is a source of amber honey and bright orange-colored pollen, rich in carotin. Redwood. — The redwood which grows at the lower altitudes in the state provides pollen of major importance for a brief period wherever it occurs in abundance. Rockrose. — The rockrose is a low shrub, woody, or herblike only at the base. The stems are numerous, tufted, and originate from a much- branched woody crown. It is reported to be rich in pollen from February to August in San Diego County, from the sea coast to 3,000 feet altitude. Rocky Mountain Bee Plant.— See "Cleome." Russian Thistle. — The well-known Russian thistle is of some value to bees as a source of pollen. San Joaquin Valley apiarists in particular have a good word for it. The plant is becoming widely abundant. 56 University of California — Experiment Station Sage. — Several species of Salvia, not listed elsewhere in this bulletin as black, purple, or white sage, are worthy of mention as important sources of nectar and pollen. At least 15 species of the genus, with a number of varieties, have been found in California. Creeping sage, 8. sonomensis, is reported important at various points in the Sierra Nevada I 1 v_ Fig. 52. — Red maids, Calandrinia caulescens var. Men- ziesii, a rich source of spring pollen in favored locations. (fig. 28) where it yields a superior quality of honey. Chia, 8. colam- bariae, is widely scattered over southern California and northward on the mountain ranges into northern California. It is visited freely by bees and no doubt is of considerable importance wherever abundant. Crimson sage or hummingbird sage, 8. spathaceae, which occurs in the coast range, does not have a good reputation as a honey plant, for it is claimed that the bees cannot get nectar from the deep blossoms. This is not the case, however, for bees in large numbers have been observed gathering nectar from this species in the Vaca Mountains on many oc- casions. Thistle sage, 8. carduacea, is common in numerous places to the Bul. 517] Nectar and Pollen Plants of California 57 south and west of Bakersfield on the plains and in mountain valleys. It is an annual requiring considerably more moisture for nectar production than is current during many seasons. It has a good reputation as a honey plant. 8. carnosa, known locally as desert sage, is a perennial blue- flowered species important for honey in the upper reaches of the Kern River. The sage worm, Platypillia marmarodactyla, is a lepidopteran insect often referred to by beekeepers as very destructive to the sage plant. Very little is known of its life history or habits, in spite of the fact that as far back as 1907 it was considered a serious pest. Apparently when conditions are favorable for sage growth the worm is forgotten. Both black and purple sage buttons are attacked even before and after blossoming. Sagebrush. — There are several native species of Artemisia, of wide distribution. They are very productive sources of yellow pollen. The sagebrush is often erroneously thought of as the true sages which are important honey plants, and belong to the genus Salvia. Silk-oak. — This tree is much used in parts of southern and central California for street and home planting. Bees visit these trees eagerly over several weeks. The honey is said to be dark and heavy. Smartweed. — These moisture-loving weeds constitute an important source of amber honey. Several species occur over the state and blossom freely toward fall. Some of the species of this genus are known as hearts- ease, knotweed, and willow-weed. Acres of solid stand have been observed in the marshlands of the Sacramento-San Joaquin delta and also below irrigation ditches in the northern end of the Sacramento Valley. The rice lands are likely to quickly become edged with these weeds. Snowberry. — The snowberry or waxberry, Symphoricarpus albus, is of wide distribution in the lower hill country of California, particularly northward. Bees visit the small blossoms eagerly for the colorless nectar. This plant constitutes an important secondary source of nectar, wher- ever abundant enough. A small bush snowberry in Siskiyou has yielded a surplus of light-colored honey of excellent quality. Other species also yield some nectar. Pollen activity of bees on these plants is practically nil. Soap Root. — This species, Chlorogalum pomeridianum, is also called soap plant, but should not be confused with the plant called by the same name but which belongs to the genus Chenopodium. The blossoms open in early evening and remain open until well into the morning. It is of wide distribution and locally abundant in the hills of the state. In Napa County, and no doubt elsewhere, it is of much value to bees, for its liberal supply of pollen and nectar. Spanish Clover. — Lotus americanus occurs widely in the state. In 58 University of California — Experiment Station some localities it is known as Mexican clover. It is abundant in Sacra- mento Valley and throughout the hills westward to the Pacific Ocean. The roadsides and fields about Sonoma afford considerable honey from this source during summer and fall. Spearmint. — This species of mint, Mentha spicata, has escaped in many wet places. Judging from the manner in which bees work it, this Fig. 53 Fig. 54 Fig. 53. — Spearmint, Mentha spicata. Fig. 54. — Pennyroyal, Mentha Pulegium. Compare with figure 53. plant (fig. 53) must secrete nectar abundantly. It has been listed as yielding amber honey in Sacramento County. The honey has a strong but delicious mint flavor. Other species of the genus of some importance here are : tule mint, Mentha arvensis; pennyroyal, M. Pulegium (fig. 54) ; and peppermint, M. piperita. The first two occur in wet patches along our north coast and inland. Bees visit them freely for nectar. The mint group of plants is reported, as a rule, to produce honey of fairly strong flavor and amber to dark in color. Spearmint and peppermint are cultivated rather ex- tensively to the north of California. Spikeweed. — One species of Centromadia known as alkali weed or Fitch's spikeweed (C. Fitchii) illustrated in figure 55, gives a yellow, Bul. 517] Nectar and Pollen Plants of California 59 rather strong-flavored honey about Davis in late summer and fall. The common spikeweed (0. pang ens) is reported as occasionally producing honey in abundance throughout the San Joaquin Valley and locally in the Sacramento Valley. There appear to be two periods of honey production from spikeweeds, one in early summer and again in early Fig. 55. — Spikeweed, Centromadia Fitchii. fall. These plants yield bright orange-colored pollen, which color, inci- dentally, is imparted to the beeswax produced from combs during the blooming period. St. Johnswort.— See "Klamath Weed." Strawberry. — Both the wild and cultivated strawberries are visited by bees for nectar and pollen, although no record of surplus honey has been reported. Sumac. — Laurel sumac, Rhus laurina, is abundant in southern Cali- fornia. In San Diego County, particularly, where it is locally referred to as mangalara, it gives a surplus honey crop. Squaw bush, R. trilobata (which is easily confused with poison oak), is widely distributed. It blossoms early in the season before the leaves come out. Lemonade-berry or mahogany sumac, R. integrifolia, is also a southern-coast species of considerable value to bees in March (fig. 56). Sugar bush, R. ovata, of 60 University of California — Experiment Station coastal southern California, blossoms in winter. Poison oak, an impor- tant source of excellent honey, also belongs to the Rhus genus, but is discussed elsewhere under its common name. Sunflower. — The common sunflower and others of the group furnish some pollen and nectar. Where abundant enough, a quantity of amber honey is stored from them in late summer and fall. The San Joaquin Valley reports the major part of the sunflower honey. Fig. 56. — A sumac, Rims integrifolia. (Courtesy, F. C. Pellett.) Sweetclover. — The sweetclovers are found throughout the state along water courses, although, probably on account of scarcity, they are not of importance any place except in the far northern part of the state. They are eagerly visited by bees everywhere. Both the biennial and annual varieties occur. Yellow sweetclover, Melilotus officinalis, is com- paratively rare in California. It blossoms earlier than the white sweet- clover, M. alba, and is worked for both pollen and nectar. This species provides larger loads of pollen that is also brighter yellow in color than the white species. Both species produce a water-white honey of excellent Bul. 517] Nectar and Pollen Plants of California 61 flavor. Certain other species of the genus including M. indica are com- mon in parts of this state but are reported to be of little value to bees. Tamarisk. — Two species of Tamarix are found in the state. T. articu- lator, frequently called athel tree, is used extensively in Imperial Valley and elsewhere as a windbreak. There the tree blossoms in summer, yielding liberal quantities of light amber honey which granulates with rapidity even in the hives. This evergreen species does not blossom at Davis, where it has been used for twenty years or more. T. gallica, called salt cedar or French tamarisk, is found very widely distributed. It is deciduous and very hardy. The blossoms are pink in color; they appear in late spring and on many plants a second time during summer. Bees work them freely for nectar and pollen. The plant is reported to give surplus honey in Arizona. Tarweed. — Many plant species are commonly called tarweeds, but most of them in California belong to the genus Hemizonia. It is a large genus of almost state-wide distribution containing several good nectar plants. One species, H. congesta, commonly called white tops (fig. 57), gives a light-colored honey of good flavor, but most of the group is re- ported to yield an amber-colored honey of somewhat strong flavor. Many of the plants are covered with a tarlike coating which has a penetrating odor. Teasel. — Fuller's teasel is a plant which yields a tremendous amount of nectar; as many as three or four bees may work a single flowering head almost continuously through the day. It is a weed in waste places, particularly along the coast. It is cultivated at times for the spiny flavor heads which are still used to some extent in combing fibers. Some ob- servers have reported bees dead, from some unknown cause, on these blossoms. Toyon. — This evergreen shrub is widely distributed up to 3,500 feet (fig. 58) and blossoms at an opportune time when many of the bees in Sacramento Valley locations have to be moved out to avoid dwindling. Toyon honey is popular and is preferred by many local customers. It is reported to yield surplus honey from Colusa, El Dorado, Monterey, Napa, Nevada, Placer, Sonoma, and other counties. The honey is very dark and thick with a decided flavor, is extracted only with difficulty, and exhibits a tendency to foam on heating. A greenish-yellow pollen is freely collected by the bees. It is also known as California holly, red- berry, or Christmasberry. Tree of Heaven. — Ailanthus glandulosa is an introduced species now widely escaped. Some of the hills of Pleasants Valley, Solano County, are thickly dotted with these trees. It yields nectar heavily in late spring; the honey is dark and strong. The objectionable flavor is reported to be 62 University of California — Experiment Station lost some time after extraction. The leaves have conspicuous glands which secrete a fluid presumed to be nectar. Tulip Tree. — Other names for this tree are cucumber tree and tulip poplar. It is used for ornamental planting in gardens and along road- ways. The flowers are very large (resembling tulips), each producing so much nectar that it may drip off. In the southeastern United States it is an important and reliable source of amber honey. Turkey-mullein. — Other local names for this plant are : dove weed, drought weed, woolly white, and yerba del pescado. It is widely scat- Fig. 57 Fig. 58 Fig. 57. — A Sacramento Valley tarweed. Fig. 58. — Distribution of toyon, Photinia arbutifolia. tered over the state, often abundant in stubble fields. Although it is not a reliable source of nectar, it sometimes yields heavily in late summer and fall. The honey is of inferior quality, and sold for use in manufac- turing or left in the hive for wintering. A grayish-white pollen is freely collected by bees. Umbrella Tree. — This tree, sometimes also known as chinaberry, is used extensively for street planting in the interior. It makes a very dense shade and is deciduous. Bees secure nectar from it at a time when the colony needs are great for brood rearing. Veratrum. — Verairum calif or nicum, commonly called corn lily or false hellebore, is usually avoided by honeybees. However, when other sources of nectar and pollen are scarce, they visit this plant. There is evidence from field observations that this plant is poisonous to them, as discussed in the section "Plants of Possible Injury to Bees." Vetch. — Both native and introduced species of vetches grow rather generally over California, particularly in the hilly orchard sections. Bul. 517] Nectar and Pollen Plants of California 63 These plants have both floral and extrafloral nectaries. Of the many kinds grown experimentally on the University Farm at Davis, but few were attractive to bees. The blossoms of hairy vetch were freely visited for nectar while those of the Hungarian variety were completely ignored. The hairy vetch is an important source of extra-light amber honey in Oregon. Virginia Creeper. — This and related climbers about our homes are eagerly visited by bees for pollen and nectar. It is too scarce to be of much value. Vitex. — Varieties of Vitex have received rather wide distribution as a honey plant by nurserymen, but are not common enough to be of much importance apiculturally. Bees and various other insects visit the pale blossoms of a number of these plants in the experimental apiary, at Davis, but secure little nectar or pollen. One of the species, V. Agnus- castus, commonly called chaste-tree, hemp tree, or monk's peppertree, is reported to be of little value to bees in Texas. Wallflower. — One of the plants known as wallflower, Erysimum as- perum, occurs commonly at 4,000 to 6,000 feet elevation in the Sierra Nevada and is an excellent source of pollen and nectar in early spring. Other members of this genus, native and cultivated, are attractive to bees wherever they occur. Walnut.— Bees collect much yellow pollen from the California black walnut, Juglans Hindsii, and also from the English walnut. The walnut aphids throw off honeydew during the summer and fall, which bees at times collect. Wax Myrtle. — This shrub or small tree, sometimes also called myrtle, is often mentioned as a honey plant along the coast. Western Black Haw. — This species, Crataegus Douglasii, is reported to be eagerly visited by bees. It occurs in canyon flats, at 2,500 to 4,000 feet elevations, from Sonoma County to Humboldt County, thence east to Modoc County. Western Hyssop. — This is a perennial herb with a distinct mint odor; the flowers are violet-purple or whitish, crowded in a terminal spike. It produces a white honey of excellent flavor. The species occurs in the San Bernardino Mountains, in the Sierra Nevada, and in the north-coast ranges, at elevations from 2,500 to 8,000 feet. Western Serviceberry. — This shrub is reported to be a source of white honey on mountain slopes of southern California and the Sierra Nevada, at 5,000 to 8,000 feet elevation, and in the coast ranges at 100 to 6,000 feet. White Clover. — The white, Dutch, or lawn clover is a famous honey plant over much of the world. It occurs in California largely in lawns 64 University of California — Experiment Station and along irrigation ditches, becoming abundant in the northwestern part of the state in meadows. The plant requires much moisture. Bees do not work it with much enthusiasm in the lowlands of California, probably because nectar is scarce in it. The larger-growing Ladino clover, recently much planted in irrigated pastures, provides a liberal supply of brown pollen and occasionally commercial quantities of a light-amber honey of excellent flavor. White Sage. — San Diego County is the chief source of honey from Salvia apiana (fig. 59). The range of the species is reported to be up to Fig. 59 Fig. 60 Fig. 59. — Distribution of white sage. Fig. 60. — White sage, Salvia apiana. 2,500 feet altitude. The plants are white in color (fig. 60). Bees appar- ently experience some difficulty in procuring the nectar, on account of the structure of the blossom, until a quantity of it is secreted. Seeds of this plant were carried to Monterey County in 1888 and the plants still persisted there in 1930 near Soledad. The honey has the same excellent qualities as that from other sages. Wild Alfalfa. — This species, Lotus scoparius, is not a true alfalfa. Other common names for it are : bird's-f oot trefoil, deerweed, and tangle- foot. It grows in dense masses on hills and mountainsides. After a fire, for perhaps three years, the burned hillsides become a tangled mass of this plant; then, when the shrubby plants grow up again, it loses its place. Figure 61 shows the blossoms and leaves. Although it gives a good yield of excellent honey in San Luis Obispo and Tulare counties, it is Bul.517] Nectar and Pollen Plants of California 65 usually a fickle yielder. The plant comes into bloom at about the same time as black sage and if gathered at the same time will cause the sage honey to granulate. Wild Hollyhock. — Sidalcea malvaeflora is of importance for nectar, and especially pollen, from January to May in the Imperial Valley, San Fig. 61. — Wild alfalfa, Lotus scoparius. Diego County, and elsewhere. It grows particularly along ditches and roadsides. The hollyhock of our gardens, Althaea rosea, everywhere yields an abundance of pollen and a little nectar for the bees throughout the summer. Wild Lilac. — The genus Ceanothus comprises a large group of plants known, not only as wild lilac, but variously as ceanothus, deerbrush, 66 University of California — Experiment Station white thorn, California lilac, and mountain lilac. The plants produce both nectar and pollen — the latter in great abundance. The honey is white and of good flavor in favorable years. The various species at differ- ing altitudes blossom over a long period of time. The common species, £§ Fig. 62. — The star thistles: purple, Centaurea calcitrapa (left) ; Napa this- tle, C. melitensis (upper right) ; and yellow, C. solstitialis. (Courtesy, T. I. Storer.) C. cuneatus, is usually spoken of as chaparral or buckbrush although these terms are also applied to numerous other shrubs. These plants are erratic in the amount of honey produced from them in that sometimes a crop of honey is obtained and again the blossoms are unattractive to bees. Willow. — This common tree is abundant over all the state along water courses and other places with abundant soil moisture. It is a very impor- tant source of nectar and yellow pollen for early brood rearing; many Bul. 517] Nectar and Pollen Plants of California 67 queen yards are located in willow areas. Insect inhabitants of willows often occasion the presence of much honeydew through the summer and fall, which is collected by the bees. Among the various species, the blos- soming season extends from early spring (pussy willow) to early sum- mer (black willow). Wisteria. — Wisteria sinensis, commonly called Chinese wisteria, is very attractive to bees for both pollen and nectar in spring, although not abundant enough to be of much value. Fig. 63. — Distribution of yellow star thistle, Centaurea solstitialis. Wood Sorrel. — Some of the plants of the genus Oxalis are freely vis- ited by bees for pollen and nectar. A yellow-flowered species in the orange groves of southern California contributes a liberal quantity of pale-red pollen during spring. Yellow Star Thistle. — A serious weed, especially in grain fields is the yellow star thistle, Centaurea solstitialis (fig. 62). It is making its ap- pearance also along the highways and railroads at many points in the state (fig. 63) . The nectar flow is a very slow one, but continuous, rarely yielding more than a can (60 pounds) of honey to the colony. This honey after extraction granulates readily, is of fine flavor, and now enjoys a special demand. The honey grades white to extra-light amber in color and has a greenish shade. Warm weather is evidently required for the best honey production. It is an important source of yellow pollen from July to October in the Sacramento Valley, the pollen being produced throughout the day. The individual heads remain in bloom for an aver- age of 11 days at Davis. Yerba Santa. — This species, Eriodictyon calif or nicum, also known as mountain balm, occurs in the hills of northern California; it has smooth, 68 University of California — Experiment Station shiny leaves and white or pale-bine blossoms. It is of much value to bees, apparently secreting nectar all day long. There is enough of it in spots to be of decided value for surplus in early summer. The honey is amber and of persistent spicy flavor. The downy-leaved species, E. trichocalyx, of southern California, is of little, if any, value for nectar. E. crassi- folium var. nivewm, is a source of nectar in the mountains west of Coal in ga. Yucca. — Among its many synonyms, Hesperoyucca Whipplei, is com- monly known as mountain queen, our Lord's candle, Roman candle, and Spanish dagger or bayonet. It is a most conspicuous plant in the southern coastwise hills and along the Sierra Nevada foothills into Fresno County. It is little visited by bees for nectar and pollen. TABLE 3 70 University of California — Experiment Station o o 3 J o 3 » <3 O o t-H CO 0J §"C 3 3-2 OS ili 3 3 u u ^ i- 1 t-, o o o o 3 c c a a c JS £ £ .5 i o 2 o .s g.s 8 o si °3 2 o § :S § § g g S dec sis 13 I O ft J | *| S 8 | §211 ji 3 .5 SSS o o fa M .fa C .2. 53 fi (D cT os S S S u -is . fa, :3 .3 Spwj^a m cj g : > £ hJ hi £ ^ <3 c3 -C s i « 03 « a «&| a5 H § fa 5 W s n s 3 ft ,3 cq oq S *£ 1 60 3 M fa J I .a I s ft § ft 3 § QQ CO 02 Hj 3 !3 3 O 3 5, a ft 3 02 > >> ,d 4S — 3-2 M ■a o> ft ^ 3 ^ j I s 3 si § O Ph pm o pm >H f> 5 *? •2 h £ o is J -^ -2 *a3 .5 "33 >< Pm I* ^ .-5 -2 © a 13 £ jj s -a >< £ pq qq O o -2 ft g S (3 °> er. ft © 3 2 '35 o « S ||1 > 03 oj ft O 2 S ."fa «S PQ ^ > PQ I ft ». ft «0 00 'S -2 Hi I!| "I 4 hi § is S *3 § 53 « -2 fa -S w g I § ■8 fe « s e c £ 3 -2 .2 *? fts^S ^ , 2 -S .« ^ °Q •« < < ?* co o 5 a> •j c >- ft -S> JS 3 in co to << bo -a ea S ^ £ P > a ^ ^ i> ft d, ^ 3 a S P CO CO S CO O a a -c >?£ g a s £ "5 g a -c >> 3 3 ft 3 © 3 3 3 3 ft p=3 3 ft CO 02 -5 © .5 3 -Nov yspr mer 5 ft ^'CB E £~ 3 a « 3 •-a co W co * 03 TJ S ^ ^ ^ c« © ^ J( ; ea .a .-5 .-3 3»©3t , 32o>s-i3 j 3 5 £ g2 ! 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