Olyra davidseana (Poaceae: Bambusoideae: Olyreae), A New Species from Brazil

Abstract

ABsTRAcr. Olyra davidseana, a new species from eastern Amazonian Brazil in the 0. glaberrima group, is described, illustrated, and compared to related species in a key. The new species is distinctive in its combination of female spikelets with attenuate glumes; smooth, shiny, female lemmas pubescent with flattened macrohairs only along the basal adaxial margins; obtuse to subcordate leaf blades; and small, congested inflorescences. The Olyreae (Poaceae: Bambusoideae) is a group of 19 genera and 80-90 species native to the American tropics. In most genera in the tribe, the species are defined by vegetative characters, the spikelets generally exhibiting little interspecific variation. The exception to this trend is Olyra L., the largest (23 species), most widespread, and most heterogeneous genus in the tribe. Species of Olyra are differentiated mainly on female floret structure, surface texture, and indument, as shown in the scanning electron micrographs presented in a recent revision (Soderstrom and Zuloaga 1989). Soderstrom and Zuloaga did not attempt an infrageneric classification of Olyra, but it is clear that besides about 10 anomalous species, there are several small, phylogenetically natural groups within the genus, such as: 1) the 0. latifolia group (0. latifolia L., 0. caudata Trin., and possibly 0. buchtienii Hackel), with smooth, shiny, presumably bird-dispersed female florets; 2) the monocarpic 0. ecaudata group (0. ecaudata Doell, 0. standleyi A. Hitchc., and 0. taquara Swallen), with inflorescences borne on separate leafless culms; 3) the 0. fasciculata group (0. fasciculata Trin., 0. obliquifolia Steudel, 0. holttumiana Soderstrom & Zuloaga, and 0. tamanquareana Soderstrom & Zuloaga), with umbel