wi37-2Zimmer.vp BRIGITTE ZIMMER Adiantum krameri (Pteridaceae), a new species from French Guiana Abstract Zimmer, B.: Adiantum krameri (Pteridaceae), a new species from French Guiana. – Willdenowia 37: 557-562. – ISSN 0511-9618; © 2007 BGBM Berlin-Dahlem. doi:10.3372/wi.37.37215 (available via http://dx.doi.org/) Adiantum krameri is described as a species new to science and illustrated. It is endemic to French Guiana (NE South America) and clearly differs from A. cordatum, with which it has so far been confused. Key words: ferns, Adiantum cordatum, NE South America. In my treatment of the Adiantum petiolatum group for Flora Mesoamericana (Zimmer 1995), I surmised that the French Guiana plants identified as A. cordatum Maxon did in fact belong to a different, undescribed species. A. cordatum was first mentioned as occurring in the centre of French Guiana by Kramer (1978) in his work on the pteridophytes of Suriname. Later a detailed description and drawings of that plant were provided (Cremers & Kramer 1985, Cremers 1997). At that time only collections from the vicinity of Saül were available. Meanwhile the same spe- cies has been recorded from further localities (Cremers & Hoff 1990, Cremers 1990). A careful study of several specimens has now confirmed my earlier hypothesis: the French Guiana plants differ from genuine A. cordatum in several features and are easy to separate from it. Therefore they are here described as a species new to science. Adiantum krameri B. Zimmer, sp. nov. Holotype: French Guiana, Montagne de la Trinité, sommet NE, in high forest near creek, c. 300 m, 4.2.1984, Granville & al. 6510 (B 20-80881!; isotypes: BR, CAY!, G, NY, P, U, Z!) – Fig. 1-2. Ab affini Adianto cordato quocum hucusque confusum differt foliorum lamina late ovata (10- 22 × 10-18 cm), latitudine aequilonga vel sublongiore (nec sesquilongiore), membranacea, costa prope basin tantum obvia, in facie adaxiali striis longitudinalibus haud notata. Plants terrestrial. Rhizome short-creeping, 3-5 mm in diameter, nodose from old pseudopodia, with several 0.5-1 mm thick rhizoids; rhizome scales reddish brown, concolourous to irregularly semi-clathrate, narrowly triangular to linear-lanceolate, often slightly denticulate. Leaves usu- ally simple, 30-70 cm long, very occasionally pinnate with 1(-2) pairs of pinnae, petiole 20-52 cm Willdenowia 37 – 2007 557 558 Zimmer: Adiantum krameri from French Guiana Fig. 1. Adiantum krameri holotype. long, 1½-2 × as long as the lamina, shiny, dark reddish brown, adaxially canaliculate with hair- like scales in the groove; costa dark brown like the petiole abaxially for 1.2-2.6 cm, becoming in- distinct in the distal half of the lamina; lamina horizontal, grey-green, membranaceous, glabres- cent above and sparingly scaly below when adult, in simple leaves ovate-orbicular, 10-22 × 10-18 cm, scarcely longer than broad, the base deeply and narrowly cordate, often with overlap- ping lobes, the apex acuminate; when fronds pinnate, pinnae similar to each other, alternate, borne on 0.7-1.4 cm long stalks, with an obliquely truncate base; young leaves pinkish, sterile margins entire; venation reticulate, evident on both sides, with 5-7-seriate, elongate areoles de- creasing in size toward the margin and apex; adaxial surface lacking idioblastic streaks. Sori con- tinuous on either side of the lamina, extending from outside the basal sinus almost to the tip; false indusia membranous, glabrous; sporangial annulus of 14-18 thickened cells. Spores trilete, c. 40-45 µm in diameter (Fig. 2). Eponymy. – The species is named in honour of Prof. Dr Karl Ulrich Kramer (1928-94), a dedi- cated, excellent pteridologist who loved to share his broad knowledge with students, fellow sci- entists and everyone interested in ferns. Distribution and habitat. – Endemic to central French Guiana and known till now from the fol- lowing three main areas (Fig. 3): Saül region (Monts La Fumée, Les Eaux-Claires, Carbet Maïs, Pic Matécho); Montagnes de la Trinité; Les Nouragues. Infrequent, terrestrial, growing in moist lowland tropical rainforests, often in deep shade, on sandy to clayey soil and granite outcrops, between 140 and 400 m above sea level. Additional specimens known (data partly supplied by M. Boudrie, G. Cremers & R. Moran). – French Guiana: Saül, = Circuit ORSTOM “Montagne la Fumée” P.K.3, forêt dense, 18.10.1972, Granville B-4602 (CAY [2 sheets]!, P, U, Z!); Saül, = Circuit ORSTOM des Monts “La Fumée”, P.K.3., forêt sur pente. 14.1.1974, Granville 2017 (CAY!, P); Saül, Layon Est sur le tracé ORSTOM sur La Montagne La Fumée, à 2,4 km, 28.10.1976, Granville B-5388 (CAY!, P, Z!); Saül, circuit La Fumée, 14.9.1978, Prévost 301 (CAY!); Saül, forêt sur colline à 3,5 km envi- ron au Nord de Carbet Maïs (20 km Est de Saül), 9.7.1979, Granville 3072 (CAY [3 sheets]!, NY, Willdenowia 37 – 2007 559 Fig. 2. Adiantum krameri scanning electron micrograph of a spore from the holotype. – Scale bar: 10 µm. P, Z [2 sheets]!; Saül, sous bois de forêt primaire, 9.3.1985, Aumeeruddy 56 (CAY!, Z!); Saül, 3°37'N, 53°12'W, near Eaux Claires along the Sentier Botanique, non-flooded moist forest, c. 200-400 m, 2.11.1990, Mori & al. 21529 (CAY!, NY); Saül, La Fumée W, lowland tropical rain- forest, 3°37'N, 53°13'W, 11.1990, Mori 21669 (NY); Saül, Eau Claire, near Saül, vicinity of gra- nitic outcrops, 200 m, 13-15.10.1993, van der Werff & al. 12986 (CAY, MO [2 sheets] photo!, NY); Saül, Pic Matécho, bord de crique, 14.12.2000, Hequet 972 (CAY); Montagnes de la Trinité, sommet nord, forêt de terre ferme, sous bois sur pente forte, 10.1.1984, Granville & al. 5848 (CAY!); Montagnes de la Trinité, zone sud, bassin de la Mana, forêt sur pente, pied de falaises au sud du massif, 300 m, 11.1.1998, Granville & Crozier 13494 (B!, CAY, K, NY, P, U, US); Station des Nouragues – Bassin de l’Arataye, 4°3'N, 52°42'W, vers le petit Plateau, forêt primaire, 30 m, 15.8.1990, Sabatier 3497 (CAY!); Station des Nouragues - Bassin de l’Approu- ague - Arataye, 4°3'N, 52°42'W, forêt de pente de basse altitude, sous-bois humide dans un petit thalweg, sur sol sablo-argileux et affleurements granitiques, 130 m, 23.2.1991, Granville 11165 (B!, BR, CAY [2 sheets]!, G, MO, NY [2 sheets], P, U, US, Z); Station des Nouragues, 12.3.1996, Solano K297 (CAY). Delimitation. – Adiantum krameri was up till now mistaken for A. cordatum Maxon (1931), de- scribed from Panama (Lectotype [designated by Zimmer 1995]: Pittier 4297, US 670422!; isolectotypes: US 670423! and US 67421!, see Fig. 4). A. cordatum does not occur in the Guia- nas, but only in Panama. It can be easily distinguished from A. krameri by the costa remaining distinct almost to the tip of the lamina, which is narrowly ovate, about twice as long as broad, lighter green and indistinctly veined abaxially, with parallel running idioblastic streaks adaxially. All material from French Guiana identified as A. cordatum or A. sp. aff. cordatum per- tains to the new species, as do the illustrations in Cremers & Kramer (1985: 3) and in Cremers (1997: 146). As A. krameri has a very distinctive look and is not easily recognized as an Adi- antum species, additional, unidentified specimens collected at other localities, perhaps even from the neighbouring Suriname, might well exist. 560 Zimmer: Adiantum krameri from French Guiana Fig. 3. The known distribution of Adiantum krameri from French Guiana. Willdenowia 37 – 2007 561 Fig. 4. Adiantum cordatum isotype (US, Pittier 4297). Acknowledgements Particular thanks are due to Werner Greuter for his assistance with the Latin diagnosis and fruit- ful discussions. I am grateful to Michel Boudrie and George Cremers for their careful and com- petent reviewing of the manuscript, and the curators of CAY, US and Z for providing specimens for study. Furthermore I thank Monika Lüchow (scanning electron microscopy), Nora Schirmer (digital photography), Ingo Haas and Angela Lautsch for technical assistance. Digital photogra- phy was funded by the friends of the Botanical Garden and Botanical Museum. References Cremers, G. 1991: Studies on the flora of the Guianas 48. Modes de repartition des ptérido- phytes de Guyane française. – Compt. Rend. Séances Soc. Biogéogr. 66: 27-42. — 1997: Adiantum Linnaeus. – Pp. 138-147 in: Mori S. A., Cremers G., Gracie C., de Granville J.-J., Hoff M. & Mitchell J. D. (ed.), Guide to the vascular plants of central French Guiana. 1. Pteridophytes, gymnosperms and monocotyledons. – Mem. New York Bot. Gard. 76. — & Hoff, M. 1990: Inventaire taxonomique des plantes de la Guyane française I. – Les ptéridophytes. – Invent. Faune Flore. Mus. Nat. Hist. Nat., Secr. Faune Flore, Paris. 54. — & Kramer, K. U. 1985: Studies on the flora of the Guianas 10. Ptéridophytes nouveaux pour la Guyane française I. – Proc. Kon. Ned. Akad. Wetensch. C 88: 1-14. Kramer, K. U. 1954: A contribution to the fern flora of French Guiana. – Acta Bot. Neerl. 3: 481-494. — 1978: The pteridophytes of Suriname. – Uitgaven Natuurwetensch. Studiekring Suriname Ned. Antillen 93: 1-198. Zimmer, B. 1995: 2. Grupo de Adiantum petiolatum. – Pp. 110-113 in: Davidse, G., Sousa, S. M. & Knapp, S. (ed.), Flora mesoamericana 1. – México. Address of the author: Brigitte Zimmer, Botanischer Garten und Botanisches Museum Berlin-Dahlem, Freie Universität Berlin, Königin-Luise-Str. 6-8, D-14195 Berlin, Germany; e-mail: b.zimmer@bgbm.org. 562 Zimmer: Adiantum krameri from French Guiana