AGRItf DEPT, 
 
STATE HORTICULTURAL COMMISSION 
 
 ELLWOOD COOPER, Commissioner 
 
 THE RUSSIAN THISTLE 
 
 ITS INTRODUCTION AND SPREAD 
 
 IN CALIFORNIA, WITH LAWS AND 
 
 MEASURES FOR ITS CONTROL 
 
 WITH A DESCRIPTION OF THE CANADA AND 
 SCOTCH THISTLES 
 
 SACRAMENTO 
 
 w. \v. SHANNON, : : : : : SUPERINTENDENT STATE PRINTING 
 
 1905 
 
STATE HORTICULTURAL COMMISSION 
 
 ELLWOOD COOPER, Commissioner 
 
 THE RUSSIAN THISTLE 
 
 ITS INTRODUCTION AND SPREAD 
 
 IN CALIFORNIA, WITH LAWS AND 
 
 MEASURES FOR ITS CONTROL 
 
 WITH A DESCRIPTION OF THE CANADA AND 
 SCOTCH THISTLES 
 
 SACRAMENTO 
 
 w. w. SHANNON, : : : : : SUPERINTENDENT STATE PRINTING 
 
 1905 
 
AGRIC. DEPT. 
 CALIFORNIA 5TATL COMMISSION OF HORTICULTURE.. 
 
 
 ELLWOOD COOPER Commissioner Santa Barbara. 
 
 JOHN ISAAC Secretary San Francisco. 
 
 ED. M. EHRHORN _. Deputy Mountain View. 
 
 E. K. CARNES Assistant Deputy Riverside. 
 
 O. E. BREMNER Second Assistant Santa Rosa. 
 
 GERTRUDE BIRD... Stenographer Sacramento. 
 
 OFFICE: 
 
 ROOM 41, STATE CAPITOL, SACRAMENTO. 
 BRANCH OFFICE, ROOM 11, FERRY BUILDING, SAN FRANCISCO. 
 
 ' " / 
 
THE RU55IAN THI5TLL 
 
 Description, and Measures for Its Control. 
 
 . 
 The Legislature of California, at its thirty-sixth session, passed an 
 
 \vhieh was approved by the Governor on March 20, 1905, increasing 
 
 the duties of the Horticultural Commissioners and local inspectors of the 
 
 di tit-rent counties by providing that they should be required to "super- 
 
 i he destruction of scale insects, diseases, Russian thistle or salt- wort, 
 
 or other noxious weeds. ' ' 
 
 This law, under the statutes, went into effect sixty days from date of 
 signing, which was on May 20th. Since the imposition of these new 
 duties upon the horticultural officers of the State, there have been 
 numerous inquiries at this office as to how the Russian thistle may be 
 recognized and what are to be considered as noxious weeds. The ques- 
 tion of what shall be considered * ' noxious weeds, ' ' we suppose, will have 
 to be left largely to the County Boards of Horticulture and the Boards 
 of Supervisors, for weeds that are exceedingly noxious in some portions 
 of the State can hardly be considered so in others; but in the matter 
 of new weeds there can be no doubt, and this is particularly true of the 
 Russian, the Canada, and the Scotch thistles, and especially so of the 
 former, which has already obtained a foothold in several of our counties, 
 but which has not as yet become so firmly established as to be beyond 
 possibility of extirpation. 
 
 From the fact that the Russian thistle is a new weed in our State, 
 there exists a vast amount of ignorance concerning it. Owing to its 
 name, which is an absurd misnomer, every species of thistle and many 
 other weeds are mistaken for it, and from various sources we learn of 
 its existence over the length and breadth of the State, but in most cases 
 our informants are mistaken. 
 
 The fact is, that, at present, this pest is confined to so limited an area 
 in California that it may be said not to exist here, and it is in order 
 that our Horticultural Commissioners and local inspectors and others 
 interested may be able to recognize this weed on sight, and also to 
 realize the great importance of totally eradicating it where it may be 
 discovered, that this bulletin is published. The necessity of this is 
 forced upon us by the fact that, since the law became operative very 
 
 337205 
 
4 THE 'RUSSIAN THISTLE. 
 
 many oi' onr Horticultural Commissioners, anxious to do their duty 
 under its provisions, have sent to this office specimens of various weeds 
 under the impression that they were the Russian thistle, but in no case 
 has this supposition been correct. 
 
 In the first place, it should be understood that the ' * Russian thistle ' ' 
 is not a thistle at all. It does not belong to the thistle family ; in fact, 
 does not resemble a thistle in any respect in its habits of growth, 
 foliage, inflorescence, seeds, or methods of distribution. It is as much 
 like a cabbage as it is like a thistle, and how it got its name is a mystery. 
 It may be that, as the uninformed in California call all plants with 
 thorns cactuses, so the Dakota farmers, when they saw that the plant 
 had prickles, concluded that all prickly plants must be thistles, and so 
 gave it this name; but if our readers want to recognize the "Russian 
 thistle," they must not look for a thistle. In its native land this weed 
 is called " Leap-the-field, " which is certainly more descriptive, and the 
 German colonists in Russia call it "wind witch." Either of these- 
 names is more suitable than that of thistle. 
 
 The Russian thistle is a tumbleweed and is somewhat related to our 
 American tumbleweed (Amaranthus albus), which, in its turn, is near 
 to our common pigweed or red-root (Amaranthus sp.). Its scientific 
 name is Salsola kali var. tragus. It is an annual, coming from seed each 
 year, and in California makes its appearance in March and April. The 
 first leaves are two small tender shoots, about an inch in length, some- 
 what resembling grass blades. Between these seed leaves the true stem 
 soon makes its appearance. This is lined with sharp-pointed, slender 
 leaves, from the axils of which branches are soon thrown out. Its growth 
 during the early stages is rather slow, and the plant, being then young 
 and tender, is eaten by stock; horses, cattle, and sheep devouring it 
 eagerly. When about two months old the plant begins to blossom: it 
 loses its tenderness, the stem becomes dry and rigid, with reddish 
 stripes, the spines on the leaves become hard, and the true leaves fall 
 off. The flowers are very small, of a greenish color, and inconspicuous, 
 each borne in the axil of a leaf and surrounded by three small, spiny 
 bracts. Although the flowers are borne separately upon the stem, they 
 appear in multitudes on the plant, and each produces its seed. 
 
 As the plant increases in age it also increases greatly in size, until it 
 forms a dense, bushy mass of spiny branches, frequently from 2 to 3 feet 
 in height and from 4 to 6 feet in diameter. Each of these branches is 
 lined its entire length with seeds, and it has been estimated that a single 
 plant of average size, from 2 to 3 feet in diameter, and weighing from 
 2 to 3 pounds, at maturity, when dry, will bear from 20,000 to 30,000 
 seeds, while there have been found single plants weighing 20 pounds, 
 with a diameter of 6 feet, which, it was estimated, would yield 200,000 
 seeds. 
 
THE RUSSIAN THISTLE. 
 
 The whole plant is horn.' upon a single, short, slender stem, half an 
 inch or less in dimmer, which, when the plant ripens, dries and becomes 
 very brittle. Under pressure of the first hard wind, it snaps off, and the 
 l goes bounding along before the wind, distributing the seeds in 
 y direction. In Dakota, specimens which had been tagged were 
 traced for a distance of from 10 to 15 miles, so it will be readily under- 
 stood that a single plant may be the cause of infesting a very large area 
 of territory in a few seasons, and the necessity of extirpating every 
 specimen on sight will be appreciated. 
 
 The seed is described as quite small, of rather peculiar shape, and the 
 whole space inside the coat is occupied by the embryo or young plant, 
 there being no albumen, as is the common condition in the grains. 
 After the plant is mature, the branches lose their red and green color 
 and become dry and bleached in appearance. The root, which is at no 
 time very well developed, then breaks off near the surface and the 
 plant is ready to start on its seed-scattering journey before the wind. 
 And it is well suited to this mode of transportation. It is light, wiry, 
 and strong; its shape is pretty nearly that of a sphere, and it goes 
 bounding across fields until it is stopped by a fence or a ditch or vegeta- 
 tion, leaving its seeds scattered over miles of surface, ready to sprout 
 as soon as favorable conditions shall arise. 
 
 The following technical description is taken from Bulletin No. 15, 
 Division of Botany, U. S. Department of Agriculture, by L. H. Dewey : 
 
 ~s,,ls<>1., l-nli tragus (L.) Moq. in D. C. Prod., XIII, 2, 187 (1849). 
 A herbaceous annual, diffusely branching from the base, 1% to 3 feet 
 (0.5 to 1 m.) high and twice as broad, smooth or slightly puberulent; 
 tap root dull white, slightly twisted near the crown; leaves alternate, 
 sessile; those of the young plant deciduous, succulent, linear or sub- 
 terete, 1 to 2 inches (3 to 6 cm.) long, spine-pointed, with narrow, 
 denticulate, membranaceous margins near the base ; leaves of the mature 
 plant persistent, each subtending two leaf-like bracts and a flower at 
 intervals of one twelfth to five twelfths of an inch (2 to 10 mm.), rigid, 
 narrowly ovate, often denticulate near the base, spine-pointed, usually 
 striped with red like the branches, three twelfths to five twelfths of an 
 inch (6 to 10 mm.) long; bracts divergent, like the leaves of the mature 
 plant in size and form; flowers solitary and sessile, perfect, apetalous, 
 about five twelfths of an inch ( 10 mm. ) in diameter ; calyx membrana- 
 ceous, persistent, inclosing the depressed fruit, usually rose-colored, 
 gamosepalous, cleft nearly to the base into five unequal divisions, about 
 one sixth of an inch (4 mm.) long, the upper one broadest, bearing on 
 each margin near the base a minute tuft of very slender coiled hairs, the 
 two nearest the subtending leaf next in size, and the lateral ones narrow, 
 each with a beak-like connivent apex, and bearing midway on the back 
 a membranaceous, striate, erose-margined horizontal wing one twelfth 
 
6 THE RUSSIAN THISTLE. 
 
 of an inch (2 mm.) long, the upper and two lower wings much broader 
 than the lateral ones; stamens five, about equaling the calyx lobes; 
 pistil simple; styles two, slender, about one twenty-fifth of an inch 
 (1 mm.) long; seed one, obconical, depressed, one sixteenth of an inch 
 (nearly 2 mm.) in diameter, dull gray or green, exalbuminous, the thin 
 seed-coat closely covering the spirally coiled embryo; embryo green, 
 slender, about one half inch (12 mm.) long when uncoiled, with two 
 linear cotyledons. The plant flowers in July or August, and the seeds 
 mature in September and October. At maturity, the action of the wind 
 causes the root to break with a somewhat spiral fracture at the surface 
 of the frozen ground, and the plant is blown about as a tumbleweed. 
 The mature flower with the inclosed seed is held in place by the minute 
 tufts of coiled hairs, preventing the seeds from falling all at once when 
 the plant begins to roll." 
 
 This plant is especially well adapted to California conditions, and 
 should it once obtain a foothold here would prove the most serious of 
 any of our imported weed-pests. It is well adapted to our arid con- 
 ditions, maturing its seed early in the season, in readiness for the first 
 north wind to start it on its journey of seed-distribution. The plant 
 is a native of eastern Europe or western Asia, where it is as unfavorably 
 known as it is now in the Dakotas. It was first introduced in the 
 Dakotas in Bonhomme County, in flax seed imported from Europe in 
 1873. In a few years it increased with terrible and destructive rapidity, 
 until in 1892, Mr. Dewey, Assistant Botanist of the U. S. Department of 
 Agriculture, estimated that the cost to the farmers of Dakota alone in 
 loss of crops was over $2,000,000 for that season. In 1893 this estimate 
 was increased for the West to from $3,000,000 to $5,000,000, and this 
 has since been largely augmented by the greatly increased area subju- 
 gated by the pest. 
 
 From a circular of Prof. L. H. Dewey, Assistant Botanist of the U. S. 
 Department of Agriculture, treating on the Russian thistle, we take the 
 following : 
 
 "The injury to crops is of course the most important item in the 
 damage caused by the Russian thistle. It takes complete possession of 
 the land, crowding out other plants. Flax, wheat, rye, barley, and oats 
 all suffer from its effects, not only in the reduction of the crop but in 
 the lower grade of that which is harvested. Corn, potatoes, vegetables, 
 and, in fact, nearly all cultivated crops are injured more or less, pro- 
 portionately to their lack of care and cultivation. 
 
 "The spiny character, added to the rigid, bushy habit of the plant, 
 makes it one of the most disagreeable of weeds to handle. When 
 mature it can not be plowed under, and it is often impossible to plow 
 fields at all until the thistles are removed. Binders can not be run 
 where the thistles are abundant, and even the working of the headers 
 
8 THE RUSSIAN THISTLE. 
 
 is seriously interfered with. The annoyance and positive injury to men 
 and animals which they cause by their rigid spines is undoubtedly 
 greater than that caused by any of the true thistles. A trouble of 
 another kind results from their being blown during prairie fires across 
 fire breaks that would otherwise be ample protection to stacks or 
 buildings. 
 
 "Warning to Pacific Coast Wheat-growers. ^&$\, of the Rocky 
 Mountains the thistle is already so widely distributed that its continued 
 progress in that region is inevitable. Its advent in Idaho and California, 
 however, is a far more serious matter. The Rocky Mountains present a 
 great natural barrier which the thistle will not easily pass, except by 
 artificial conveyance. With the natural conditions thus favorable to its 
 exclusion, and with a full knowledge of the disastrous nature of the 
 scourge, it is almost criminal to allow it to become established west of 
 the Rockies. To the Pacific Coast the Sierra Nevada and Cascade 
 mountains afford additional protection, but some seed will be sure to 
 find its way over this barrier also, especially if the thistle is allowed to 
 obtain a hold in the Great Basin. In view of these facts, the California 
 wheat-grower should take precautions against the weed, opposing both 
 its direct introduction into California from the plains east of the Rockies 
 and its gradual advance by way of the Great Basin. 
 
 "The plant is an annual, easily killed at any time during the growing 
 season. It produces no seed before the middle of August or first of 
 September, and the seed is short-lived. The circumstances, therefore, 
 are exceptionally favorable for its being checked, or even exterminated. 
 In order to secure a complete extirpation these two conditions must be 
 fulfilled: 
 
 "1. No Russian thistle shall be allowed to produce seed. 
 
 "2. There must be concerted action throughout all the infested area. 
 
 "If the Russian thistle, wherever found, should be killed before it 
 produces seed during three successive years, the pest would in all 
 probability be completely exterminated; for the experiments already 
 made indicate that the vitality of the seed is lost within that period. 
 But since the ground is so easily reseeded from a neighboring crop, if 
 action is not taken everywhere and at one time the work will have to 
 be done over indefinitely. 
 
 "In the absence of universal concerted action, as extensive coopera- 
 tion as possible should be secured ; and at all events each farmer should 
 protect his own farm as well as he may, in doing which he will also 
 avoid injuring his neighbor. The want of cooperation is a great dis- 
 advantage. Farmers in some instances have so far succeeded in keeping 
 
THE RUSSIAN THISTLE. 9 
 
 the weed under that their crops have been little injured, but it has 
 cost a great deal in extra labor, and they have been compelled to fight 
 it every year h.-cause of -seed blown in from adjacent lands. On the 
 other hand, the farmer who has not attempted to drive the weed from 
 his farm has sustained immense damage to his crops, and in some cases 
 has even been driven from his farm. 
 
 "Remuli'* in Cultivated Fields. Wheat and other spring crops 
 should be sowed as early as possible on well-prepared land, so that the 
 crop may get a vigorous start and shade the ground before the weed 
 seeds germinate. The wheat may then be cut early, when there is less 
 da 111:1 -r that the thistle plants will be large enough to cause trouble in 
 harvesting. By such a plan this and many other weeds growing in the 
 stubble may be destroyed before they produce seed. 
 
 * ' The land should be plowed as soon as possible after the wheat is cut, 
 and if this can not be done before the first of September the stubble 
 should be burned. The thistle is still rather juicy in August and burns 
 with difficulty, so that it is advisable to mow the stubble and let it dry 
 a few days before firing. In this connection the importance of harvest- 
 ing with a header is to be emphasized, as the greater amount of stubble 
 left by this process furnishes material for a more thorough burning. 
 The land should be plowed or the stubble burned immediately after 
 harvesting a crop of barley, rye, or oats. 
 
 "Crops like corn, potatoes, and^beets should be kept thoroughly culti- 
 vated as late as possible. The extra cultivation will produce a better 
 crop as well as kill the weeds. Several cornfields seen in the fall of 
 1893 evidently produced a much better crop of Russian thistles and 
 pigeon grass than of corn, while other fields near by, apparently with 
 the same kind of soil, but free from pigeon grass and the Russian thistle, 
 bore a corn crop fifty per cent better. Such crops should be cultivated 
 until they thoroughly shade the ground, and if thistles appear after 
 that the hoe should be used, so that none may be allowed to produce 
 seed. Potato fields and gardens devoted to early crops should receive 
 better attention than heretofore. When cultivated only enough to 
 produce a crop and allowed to remain unworked after the middle of 
 July these places usually produce an enormous number of large thistle 
 plants. Many such fields were seen during the autumns of 1892 and 
 1893 which might have been plowed for $5 or less, or even planted with 
 a paying second crop, but instead were left to produce a crop of weeds, 
 which might easily cause damage to the extent of hundreds of dollars. 
 
 "If summer-fallowing is practiced, the land should be plowed late 
 
 the spring, so that seeds near the surface will have germinated and 
 young plants be killed. The harrow or cultivator should be kept 
 
 use during the summer. The thorough cultivation will improve the 
 
 idition of the soil for future crops as well as keep the weeds from 
 
2. Branch from Russian thistle, showing appearance of plant when seeds are 
 mature; a, branch from a young plant, showing the appearance before 
 the dry season; b, mature seed, enlarged five times. (From U. S. Dept. oi 
 Agriculture.) 
 
FMULLCA 
 
 . -Branch of Russian thistle, showing appearance before flowering and before the spiny 
 
 branchlets have elongated ; a, spines, enlarged ; b, young grain with the covering 
 
 removed, enlarged about seven times: e, lilosM.m removed from the axil and viewed 
 
 from below, enlarged about four times: <l. section of fruiting calyx, side view; e, same, 
 
 Q frin above. (From U. S. Dept. of Agriculture.) 
 
12 THE RUSSIAN THISTLE. 
 
 seeding. This is the theory of summer-fallowing, but, unfortunately, 
 it has seldom been fully carried out in the Dakotas and adjoining 
 States. The land there has usually been left untouched after the 
 spring plowing. Instead of a barren fallow or 'resting period/ a crop 
 of weeds is grown, which drains the land almost as much as a crop of 
 grain, and the soil, instead of being cleared of weeds, becomes a veri- 
 table hotbed of them. Summer-fallowing, even if the land is kept 
 barren by cultivation, gives comparatively little benefit except to clear 
 out the weed seed. This object may be attained just as well by raising 
 a crop which will pay the expenses of cultivation. Beans, peas, clover, 
 millet, or rye may be sown, pastured, and plowed under for green fer- 
 tilizer at little expense, and it will improve the land vastly more than 
 barren fallowing. Millet and oats combined may be grown and cut for 
 hay. This crop will choke out nearly all weeds, while the few that do 
 grow will be slender and weak, producing comparatively few seeds, and 
 many will be cut with the hay before producing any seed. 
 
 "Roadsides, Fire Breaks, and Waste Places. If the Russian thistle is 
 to be kept out of cultivated fields it must be exterminated on roadsides, 
 fire breaks, and waste land where the sod has been broken, and in all 
 places where it has obtained foothold. 
 
 * ' In many places the prairie roads, which are usually mere unf enced 
 driveways, are lined on each side by hedges of robust Russian thistles 
 growing between the beaten track and the prairie grass, as ragweeds 
 grow along roads in the East. A road machine may here be used to 
 good advantage, the scraper being so set as to take as thin a layer of 
 earth as possible, and weeds and all being thrown to the middle of the 
 track. Fire breaks can be kept free from the Russian thistle and other 
 weeds most economically by frequent use of the harrow. When covered 
 with large dry tumbleweeds, as they frequently are, instead of being 
 a protection they become a source of great danger in times of prairie 
 fires. 
 
 "In the sand hills, on public lands, and in the scattered weed patches 
 of cattle ranges there seems to be no direct compensation for the labor 
 expended in exterminating the weeds. The thistles, however, must 
 be destroyed in these places, and the work may be done at a cost small 
 in comparison with the damage these plants would cause if allowed to 
 produce seed. 
 
 "The great windrows of Russian thistles found banked up against 
 wire fences in early winter suggest the use of fences to check the dis- 
 semination of the weed by rolling. The thistles, however, will easily 
 bound over a fence, especially after a bank reaches its top ; and at any 
 time the whole pile is liable by a shift in the wind to be sent off in some 
 other direction. Prompt burning would be of some value, and this 
 would be possible if metallic fence posts were used. 
 
THE RUSSIAN THISTLE. 13 
 
 "Like all noxious weeds, the Russian thistle may be kept out much 
 more easily than it can be eradicated when once established. In regions 
 not yet infested all avenues of introduction should be watched so that 
 it may be discovered and killed before it can obtain a footing. 
 
 ' * It may be expected along all lines of railroads, especially those hav- 
 ing direct traffic with infested regions. It is by way of the railroads that 
 the seeds most often enter new territory, being dropped from stock or 
 grain cars at stock yards, elevators, and sidings. The plants usually 
 appear first close along the tracks by the ends of the ties, where the 
 seeds falling from the cars find conditions favorable to growth in the 
 unoccupied soil, kept stirred by repairs on the tracks and the ballast. 
 
 1 1 The seeds have been introduced in some cases in baled hay and grain 
 at fair grounds, race tracks, lumber camps, and railroad construction 
 camps. They have also been carried in shelled corn, wheat, oats, millet, 
 flax, alfalfa, and grass seed. They are supposed to have been brought 
 to some localities in Idaho in sheep's wool. While the seed has no 
 hooks, barbs, or gum to cause it to stick like cocklebur or clammy 
 cuphea, its small size and light weight enable it to retain a place for 
 some time in a fleece. 
 
 "Another means of introduction and rapid distribution, and one that 
 threatens to be most troublesome, is running water. During the past 
 three years the thistle has spread with remarkable rapidity over irri- 
 gated lands in Colorado and Idaho. Robust plants are produced on 
 the banks of the irrigating canals and ditches. The seeds from these 
 are carried long distances by the water and deposited in the fields. In 
 some cases quarter-sections of irrigated land have been practically 
 covered with the Russian thistle in a single season. The plants have 
 also spread along river banks, especially during freshets. 
 
 "These sources of introduction should be carefully guarded, and 
 every Russian thistle seen should be destroyed before it has produced 
 seed. If any escape notice until the seeds are mature they should be cut 
 and burned before they begin to roll. One Russian thistle destroyed 
 this year is likely to obviate the necessity of destroying from 1,000 to 
 100,000 next year." 
 
 "Efforts have been made to check the progress of tumbleweeds or, 
 at least, of the Russian thistle, by building fences. Thase efforts have 
 been successful only in a very small degree, as the weeds pile up and are 
 blown over the tops of the fences, and also the detached seeds are blown 
 through. In any case the only safe and thoroughly effective method 
 is to destroy the weeds before the seeds reach maturity." (Yearbook, 
 1896.) 
 
14 THE CANADA THISTLE. 
 
 * ' The plant seems to be particularly a railway weed. It has appeared 
 first along the railways in sixteen of the twenty-one States and Terri- 
 tories in which it has been introduced. In nearly all the States where 
 it is now found its wide circulation has been chiefly by railways, in 
 spite of the fact that railway companies have generally done more than 
 all other parties to combat it." (Yearbook, 1896.) 
 
 CANADA THISTLE. 
 
 The Canada thistle, so called, is altogether a different plant from the 
 Russian stranger, and is a true thistle. This pest is known by various 
 local names, as "cursed thistle," "corn thistle," "hard thistle," and 
 "creeping thistle," but by whatever name called it is always the same 
 costly, unconquerable enemy of the farmer. This plant, although 
 known as the Canada thistle, is a native of Europe and reached our 
 country by Newfoundland, from which point of entry it has now 
 spread west to Nebraska and south beyond Virginia. Like the great 
 pests of our California farmers, the dreaded morning-glory and the 
 Johnson-grass, it creeps through the soil by means of root-stocks and it 
 is almost, impossible to eradicate it, as every piece of root left in the 
 ground forms a new plant, and the more it is cut up the more it thrives. 
 
 The following description of the thistle is given by Prof. Moses Craig, 
 Botanist of the Oregon Agricultural Experiment Station: 
 
 "This plant differs from the common Bull thistle, for which it is 
 often mistaken, in its slenderer, wingless stem and branches, in the thin, 
 narrow (% to % inch), curled and more deeply cut leaves, less rigid 
 prickles, and smaller flower heads which are about half an inch in 
 diameter. It is more difficult to destroy than the common thistle, as it 
 is a perennial, spreading by long underground stems, which penetrate 
 deeply into the soil, often below the reach of the plow. These rhizomes 
 extend horizontally in all directions, and being furnished with buds 
 send branches to the surface, where a tuft of leaves is first produced, 
 followed later by aerial stems, which bear flowers and seed. These die 
 down to the ground every fall, but in the spring the rhizomes again send 
 up numerous branches, which soon cover the ground, the plants spread- 
 ing with surprising rapidity from year to year. 
 
 "This 'Cursed Thistle' is also propagated by seeds, which, supported 
 by the downy pappus, are often carried long distances by the wind. 
 Like most of our troublesome weeds it was introduced from Europe 
 and has now become permanently established in this country. It has 
 been reported from nine counties in Oregon, where fortunately it is 
 not abundant. 
 
 "Cnicus arvensis, Hoffra. Fl. Germ. IV 180 Perennial and spreading by creeping 
 root-stalks a foot or two high, corymbosely branching, usually glabrate and green; 
 
THE SCOTVH'TJH.- 15 
 
 .-tern and branches wingless : leaves lanceolate, pinnatifid and toothed, furnished 
 with abundant weak prickles; heads loosely cymose, less than an inch high, 
 iliu'dous; in male plant ovate-globular, and flowers (rose-purple) well exserted ; in 
 female oblong-campanulate and flowers less projecting; bracts of involucre all 
 impressed. sh"i't, and with very small weak prickly points; only abortive anthers 
 to the female flowers. Meadows, pastures, and waste grounds, from Newfoundland 
 through the Northern and Middle Atlantic States: a too common weed. (Nat. 
 from Eu.) 
 
 ' Frequent deep plowing will, in shallow, dry soils, nearly always 
 destroy the thistle, but in light, rich, moist soils this usually fails. 
 Wherever a dense sod can be formed seeding will be found the easiest 
 moans of destruction, though not so rapid as plowing, hoeing, salting, 
 or burning where these means are available. On rich bottom lands or 
 in ground filled with stumps, a grass sod will be found the best 
 destroyer. If the land is not rich enough to form a good sod manure it. 
 
 "Mowing when the thistle is coming into bloom does not destroy the 
 plant, though it checks its growth. The application of kerosene or strong 
 orine to the roots, after cutting off the tops three or four inches below 
 the crown with a spade, is effective and practicable in small patches. 
 In stony ground the scythe, salt, and sheep will be found good destroy- 
 ing agents. If the thistles are in fence rows move the fence, and plow. 
 
 "One object of thorough cultivation is that all weed seeds may 
 germinate and be destroyed at once and not lie dormant in the ground, 
 coming up a few at a time to reseed the field. Plowing and stirring the 
 soil when infested with Canada thistles, unless thoroughly done, only 
 multiplies them, so do not permit any leaves or underground stems to 
 remain, but burn the plants immediately after cutting. The cultivation 
 need not be deep. If all the thistles are kept cut off three inches below 
 the surface the underground portions will soon die of exhaustion." 
 
 SCOTCH THISTLE. 
 
 The Scotch thistle (0 nor pud um acanthium), or Cotton thistle, has not 
 yet made its appearance as a weed in California, and it is not nearly 
 so much to be feared as either the Russian thistle or the Canada thistle. 
 It is well, however, to take precautions against its introduction, for 
 while it is not a serious pest in its native land, the changed conditions 
 of California might also change its character. It has already obtained 
 a permanent foothold in some parts of the East, but does not rank as 
 a weed of the first class. It is easily kept in check by vigorous culti- 
 vation and by cutting down the plants close to the ground before 
 blossoming. 
 
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