BULLETIN OF THE TORREY BOTANICAL CLUB

VOL. 104, No.1, pp. 10-11 JANUARY-~IARCH 1977

Clematis coahuilensis (), a new species from north-central Mexico1 David J. Keil Department of Botany and Microbiology State University, Tempe, Arizona 85281 KEIL, D. J. (Dept. Bot. Microbiol., Arizona State Univ., Tempe 85281). coahuilensis (Ranunculaceae), a new species from north-central Mexico. Bull. Torrey Bot. Club 104: 10-11. 1977.-Clematis coahuilensis is described as new froln mOUll­ tainous regions of Coahuila, Durango, and Nuevo Leon, Mexico. The new species is a member of sect. Clematis and is contrasted with C. dioica L. and C. drumrnondii T. & G.

Floristic investigations in the Cuatro flowered sessile or short-peduncled cymes. Cienegas basin and nearby mountain ranges In some individuals of C. coahtttilensis, in Coahuila, Mexico, have resulted in the cymes are loosely aggregated into paniculi­ discovery of a previously undescribed form clusters (Fig. 1). species of Clematis (Ranunculaceae). The Clematis drummondii is vegetatively new species, Clematis coahuilensis, is ap­ quite distinct from C. coahuilensis but has parently restricted to the Chihuahuan similar inflorescence form. Leaves of C. Desert Region and adjacent segments of drummondii are very long-petiolate and the Sierra Madre Oriental. Its known dis­ are once or sometimes twice-pinnate. Leaf­ tribution is centered in Coahuila. lets are usually deeply incised with the Clematis coahuilensis is a member of terminal lobe elongate and often falcate. sect. Clematis. The closest relatives appear Margins of the lobes are either slightly con­ to be two rather dissimilar species, C. dioica vex-curved or weakly concave-curved. L., a widespread tropical American taxon. Pedicels in C. drummondii range from 0.5 and C. drummondii T. & G., a common to 0.9 mm diameter whereas those of C. of arid regions of North America. Clematis coahuilensis are more slender (0.3-0.5 mm coahuilensis is allopatric with C. dioica but diameter). Styles of C. coahuilensis seldom is geographically sympatric with C. drum­ exceed 3.5 cm in length, but in C. drum­ mondii. mondii, styles are very elongate, ranging The principal similarities between C. from 4 to 10 cm. coahuilensis and C. dioica are vegetative. Although C. coahtttilensis and C. drum­ Leaves of both species are once pinnate mondii occur in the same regions, they are with 3-5 (-7) ovate, entire to few-dentate ecologically distinct. Clematis coahtttilensis or shallowly lobed, often coriaceous leaf­ grows in upland canyons between 1200 and lets. Leaves of C. coahuilensis are generally 2400 m in the oak-pine woodland and chap­ smaller than those of C. dioica, although arral scrub zones. Clematis drummondii is leaf size is rather variable in both taxa. widespread mostly at lower elevations. It Inflorescences of C. dioica are usually axil­ is particularly common along roadsides and lary or terminal, long-peduncled corymbi­ fences where the long plumose styles of its form compound cymes. In C. coahuilensis fruits make it a conspicuous element of the flowers are solitary or clustered in few­ flora. Clematis coahuilensis Keil, sp. nov. Frutex scandens caulibus usque ad 3 1 I would like to thank Dr. Donald J. Pinkava for bringing this new species to my attention and vel 4 m longis, infra inflorescentes inter­ for his support and encouragement throughout the nodis 4-13 cm longis et 1-2 mm diametro, study. I am grateful to Dr. Marshall C. J ohnstoD virescentibus vel atrospadiceis sexangu­ and Dr. James S. Pringle for reviewing the manu­ laribus tomentosis vel glabrescentibus. script. 2 Present address: Biological Sciences Dept., Folia semel pinnata, plerumque 6-11 cm California Polytechnic State University, San Luis longa; petioli exiles interdum volubiles, Obispo, CA 93407. 1.0-4.5 cm longi, villoso-tomentosi; rhaches Ree.eived for publication June 8, 1976. 1-4 em longi, villoso-tomentosi; foliola 3-7, 10 ID77] KEIL: CLE~IATIS COAHUILENSIS A NE'V SPECIES FROM: l\IEXICO 11

­1cm Figs. 1-2. Clematis coahuilensis, sp. nov.-Fig. 1. a, habit; b, staminate flower; c, mature achene~ -Fig. 2. Geographic distribution of Clematis coahuilensis. sessilia usque longipetiolulata, subcoriacea, TYPE: Mexico: Coahuila: Sierra de la late lanceolata usque ovata, 1-5-nervata, Madera, Ca:fion de la Hacienda, 1400 ill, 2-5 (-6) cm longa et 1-3 (-5) cm lata, 4 Aug 1973, <1', J. Henrickson & T. Wendt integra usque paucidentata et/vel trilobata 11880 (holotype, LL; isotypes, ASU, re­ dentibus apice mucronatis, marginibus mainder to be distributed). foliolorum loborumque convexis, basibus Clematis coahuilensis is known from rotundatis vel subcordatis, apicibus obtusis mountainous areas of Coahuila, northeast­ usque acuminatis, utrinque atrivirentia seu ern Durango, and western Nuevo Leon subtus parum pallentioria, utrinque pilosa (Fig. 2) and is known in flower or fruit trichomatibus exilibus 0.3-0.8 mm longis from late June to mid-September. aut glabrescentia, subtus stomatophora. Additional specimens examined: Mex­ Cymae 1-5-florae floribus nunc solitariae ico: Coahuila: Sierra de la Madera, Ca:fion axillaresque nunc in paniculis foliosis usque de la Charretera, S?, I. M. Johnston 9131 ad 20 cm longis, pedicellis filiformibus 0.3­ (GR, LL), <3', 9131A (GR, LL) ; Cafion de 0.5 mm diametro, 0.7-2.5 cm longis, tomen­ la Gavia, S of Rancho de la Gavia, d', M. tosis. Flores staminati 2 cm diametro, re­ C. Johnston et ale 12046 (LL); Muzquiz, ceptacula conica hirtella, sepalis 4, eburneis Maripos.a Ranch, Palm Canyon, :S?, Marsh oblanceolatis circa 1 cm longis 3-4 mm latis '7d (TEX) ; Sierra de la Gloria,(J', Marsh patentibus utrinque tomentulosis, stamin­ 1865 (GR), I(J', Marsh 1981 (GR, TEX) ; ibus numerosis usque ad circa 8 mm longis, Sierra de la Madera, Ca:fion del Pajarito, interdum aliquot pistillis rudimentalibus. (f, S?, Muller 3155 (GR, LL); Sierra de Flores pistillati non visi. Receptaculum San Marcos, 4 mi NW of Poso de los fructiferum conicum hirtellum. Achenia Fresnos, bud only, Reeves & Pinkava complanata elliptica, 3.5-4.0 mm longa, P13163 (ASU). Durango: NW third of 2.0-2.5 mm lata, atroporphyrea, hirtella, Sierra del Rosario, J, M. C. Johnston et ale stylibus plumosis 2-4 cm longis. Chromo­ 11459C (LL). Nuevo Leon: Lampazos, <3', somatum numerus ignotus. Taylor 353 (TEX).