Guayania davidsei and Hebeclinium gentryi, New Species from Northern South America (Eupatorieae-Asteraceae)

Abstract

Descriptions and discussions of relationships are provided for Gulayania davidsei R. M. King & H. Robinson from the Amazonas region of Venezuela and Hebeclinium gentryi R. M. King & H. Robinson from the Choco region of Colombia. Collecting efforts of two members of the staff of the Missouri Botanical Garden have provided two new species belonging to the Hebeclinium complex of the tribe Eupatorieae (King & Robinson, 1971a, 1971b). The complex is notable for the partially deciduous subimbricate involucral bracts, the simple structure of the style base, the smooth corolla lobes, the long nonannulated anther collars, and for a tendency to bear hairs on the receptacle. The latter character which was the traditional distinction of Hebeclinium is, however, not consistent throughout the group, being absent in some species of Hebeclinium sens. str. and lacking in all species of Guayania. The genera Hebeclinium and GCuayania are most easily distinguished by the extremely filiform style appendages of the former and by the strongly asymmetric carpopodium of the latter. With the present additions Hebeclinium has 19 species concentrated in the northern Andes with one species, H. macrophyllum (L.) DC., widely distributed. Guayania now contains 6 species all restricted to the Guayana Highlands region and to the surrounding lowlands of the Orinoco and Amazon. Guayania davidsei R. M. King & H. Robinson, sp. nov.-FIG. 1. Plantae herbaceae perennes erectae ca. 4 dm altae pauce ramosae. Caules succulenti anguste jatrophiformes superne abbreviati et in inflorescentia abrupte terminati glabri et in sicco irregulariter striati. Folia opposita superne congesta, petiolis 4-6 cm longis; laminae ovatae 9-12 cm longae et 6.0-7.5 cm latae penninervatae base late obtusae margine serratae apice vix breviter acumninatae supra et subtus glabrae vel ad marginem sparse puberulae. Inflorescentiae laxe cymosae, ramis dense puberulis, pedicellis 0.3-1.5 mm longis. Capitula 5.0-5.5 mm longa et 3-4 mm lata; squamae involucri ca. 28 et 4-5-seriatae 1.0-4.5 mm longae ad 1 mm latae exteriores late ovatae interiores sensim oblongae vel anguste lanceolatae margine et apice distincte scariosae et minute puberulae apice late vel anguste rotundatae extus glabrae et plerumque 3-striatae; receptacula leniter convexa glabra. Flores ca. 22 in capitulo; corollae albae tubulosae ca. 3 mm longae, faucis tubulosis base indistinctis, lobis ca. 0.3 mm longis et 0.25 'This study was supported in part by the National Science Foundation Grant DEB7713457 to the senior author. 2Department of Botany, United States National Museum, Smithsonian Institution, Washington, D.C. 20560. ANN. MIssouRI BOT. GARD. 64: 366-370. 1977. This content downloaded from 157.55.39.249 on Wed, 03 Aug 2016 05:31:32 UTC All use subject to http://about.jstor.org/terms 1977] KING & ROBINSON-GUAYANIA AND HEBECLINIUM 367