Family: Poaceae |
J.K. Wipff and Rahmona A. Thompson Plants annual or perennial; usually cespitose, sometimes mat-forming, sometimes stoloniferous. Culms 5-500 cm, herbaceous, erect, geniculate, or decumbent and rooting at the lower nodes. Sheaths open; auricles rarely present; ligules apparently of hairs, the basal membranous portion inconspicuous; blades ovate-lanceolate to lanceolate, flat. Inflorescences terminal or terminal and axillary, usually panicles of spikelike primary branches in 2 or more ranks, rachises not concealed by the spikelets; primary branches usually alternate or subopposite, spikelike, and 1-sided, less frequently verticillate, axes flat, triquetrous or crescentic in cross-section, usually terminating in a well-developed, rudimentary spikelet; secondary branches present or absent; disarticulation beneath the spikelets. Spikelets solitary, paired, or in triplets, subsessile or pedicellate, divergent or appressed, ovoid to ellipsoid, dorsally compressed, in 1-2(4) rows, with 2 florets, lower or upper glumes adjacent to the branch axes. Glumes not saccate basally; lower glumes usually 1/5-2/3 as long as the spikelets, occasionally equaling the upper florets, (0)1-11-veined; upper glumes 5-13-veined; lower florets sterile or staminate; lower lemmas similar to the upper glumes, 5-9-veined; lower paleas if present, usually hyaline, 2-veined; upper floretsbisexual, sessile, ovoid to ellipsoid, usually plano-convex, usually glabrous, not disarticulating, mucronate or acuminate; upper lemmas indurate, transversely rugose and verrucose, 5-veined, margins involute, apices round to mucronate, or aristate; upper paleas rugose, shiny or lustrous; lodicules 2,cuneate, truncate; anthers 3. Caryopses ovoid to elliptic, dorsally compressed; embryos 1/2-3/4 as long as the caryopses; hila punctate to linear. x = 7, 8, 9, or 10. Name from the Greek ouros, tail and chloa, grass, a reference to the abruptly awned lemmas of some species. There are 19 species of Urochloa in the US, 8 established introductions, 6 native, and 3 cultivated as grain or forage crops, The remaining 2 have been found in the U.S. but are not known to be established there. SELECTED REFERENCES Aliscioni, S.S., L.M. Giussani, F.O. Zuloaga, and E.A. Kellogg. 2003. A molecular phylogeny of Panicum (Poaceae: Paniceae): Tests of monophylly and phylogenetic placement within the Panicoideae. Amer. J. Bot. 90:796-821. Clayton, W.D. and S.A. Renvoize. 1982. Flora of Tropical East Africa. Gramineae (Part 3). A.A. Balkema, Rotterdam, The Netherlands. 448 pp.; Davidse, G. and R.W. Pohl. 1994. Urochloa P. Beauv. Pp. 331-333 in G. Davidse, M. Sousa S., and A.O. Chater (eds.). Flora Mesoamericana, vol. 6: Alismataceae a Cyperaceae. Universidad Nacional Autónoma de México, Instituto de Biología, México, D.F., México. 543 pp.; Fox, W.E., III and S.L. Hatch. 1996. Brachiaria eruciformis and Urochloa brizantha (Poaceae: Paniceae) new to Texas. Sida 17:287-288; Giussani, L.M., H. Cota-Sanchez, F.O. Zuloaga, and E. A. Kellogg. 2001. A molecular phylogeny of the subfamily Panicoideae (Poaceae) shows multiple origins of C4photosynthsis. Amer. J. Bot. 88:1993-2012; Gomez-Martinez, R. and A. Culham. 2000. Pp. 136-140 in S.W.L. Jacobs and J. Everett (eds.). Grasses: Systematics and Evolution. International Symposium on Grass Systematics and Evolution (3rd:1998). CSIRO Publishing, Collingwood, Victoria, Australia. 408 pp.; Hall, D.W. 1978. The Grasses of Florida. Ph.D. dissertation, University of Florida, Gainesville, Florida, U.S.A. 498 pp.; Morrone, O. and F.O. Zuloaga. 1992. Revisión de las especies Sudamericanas nativas e introducidas de los géneros Brachiaria y Urochloa (Poaceae: Panicoideae: Paniceae). Darwiniana 31:43-109; Morrone, O. and F.O. Zuloaga. 1993. Sinopsis del género Urochloa (Poaceae: Panicoideae: Paniceae) para México y America Central. Darwiniana 32:59-75; Munshi, J.D., V. Bankisar, J.K. Pal, and N. Pandit. 1995. Cytomixis and chromosome variation in Brachiaria ramosa (L.) Stapf from Diara Land of Bhagalpur, Bihar. Proc. Indian Sci. Congr. 82:73; Pohl, R.W.1980. Flora Costaricensis: Family #15, Gramineae. Fieldiana, Bot., n.s., 4:1-608; Reed, C.F. 1964. A flora of the chrome and manganese ore piles at Canton, in the Port of Baltimore, Maryland and at Newport News, Virginia, with descriptions of genera and species new to the flora of the eastern United States. Phytologia 10:321-405; Sendulsky, T.1978. Brachiaria: Taxonomy of cultivated and native species in Brazil. Hoehnea 7:99-139; Simon, B.K. and S.W.L. Jacobs. 2003. Megathyrsus, a new generic name for Panicum subgenus Megathyrsus. Austrobaileya 6:571-574; Veldkamp, J.F. 1996. Brachiaria, Urochloa (Gramineae-Paniceae) in Malesia. Blumea 41:413-437; Webster, R.D.1987. The Australian Paniceae (Poaceae). J. Cramer, Berlin and Stuttgart, Germany. 322 pp.; Wipff, J.K., R.I. Lonard, S.D. Jones, and S.L. Hatch. 1993. The genus Urochloa (Poaceae: Paniceae) in Texas, including one previously unreported species for the state. Sida 15:405-413; Zuloaga, F.O., O. Morrone, and L.M. Giussani. 2000. A cladistic analysis of the Paniceae: A preliminary approach. Pp. 123-135 in S.W.L. Jacobs and J. Everett (eds.). Grasses: Systematics and Evolution. International Symposium on Grass Systematics and Evolution (3rd:1998). CSIRO Publishing, Collingwood, Victoria, Australia. 408 pp. Plants annual or perennial; usually cespitose, sometimes mat-forming, sometimes stoloniferous. Culms 5-500 cm, herbaceous, erect, geniculate, or decumbent and rooting at the lower nodes. Sheaths open; auricles rarely present; ligules of hairs; blades ovate-lanceolate to lanceolate, flat. Inflorescences terminal or terminal and axillary, usually panicles of spikelike primary branches in 2 or more ranks, rachises not concealed by the spikelets; primary branches usually alternate or subopposite, spikelike, and 1-sided, less frequently verticillate, axes flat, triquetrous or crescentic in cross-section, usually terminating in a well-developed, rudimentary spikelet; secondary branches present or absent; disarticulation beneath the spikelets. Spikelets solitary, paired, or in triplets, subsessile or pedicellate, divergent or appressed, ovoid to ellipsoid, dorsally compressed, in 1-2(4) rows, with 2 florets, lower or upper glumes adjacent to the branch axes. Glumes not saccate basally; lower glumes usually 1/5-2/3 as long as the spikelets, occasionally equaling the upper florets, (0)1-11-veined; upper glumes 5-13-veined; lower florets sterile or staminate; lower lemmas similar to the upper glumes, 5-9-veined; lower paleas if present, usually hyaline, 2-veined; upper florets bisexual, sessile, ovoid to ellipsoid, usually plano-convex, usually glabrous, not disarticulating, mucronate or acuminate; upper lemmas indurate, transversely rugose and verrucose, 5-veined, margins involute, apices round to mucronate, or aristate; upper paleas rugose, shiny or lustrous; anthers 3. Caryopses ovoid to elliptic, dorsally compressed; embryos 1/2-3/4 as long as the caryopses; hila punctate to linear. x = 7, 8, 9, or 10. Name from the Greek ouros, tail and chloa, grass, a reference to the abruptly awned lemmas of some species. Urochloa, as interpreted here is a genus of approximately 100 tropical and subtropical species. It used to be treated as an Old World genus of about 12 species but research has strongly supported its expansion to include many species that had been included in Brachiaria. Its boundaries are still being examined. Phylogenetic research by Salariato et al. (2010) supports further expansion of Urochloa, most notably to include Eriochloa, but the names needed to implement such an expansion have not been made. Four species (Urochloa brizantha, Urochloa decumbens, Urochloa panicoides, and Urochloa ruziensis) are widely cultivated as forage species in tropical areas. Cope, in the Flora of Somalia adopted the traditional treatment of Urochloa. Under this revised treatment, the genus is represented by at least 13 species. Some of the species still treated in Brachiaria may belong in Urochloa. A new key for the species of Somaliland and Somalia now included in Urochloa is in development (20 Feb 2021). The description above is simplified a little from that published in Flora of North America, but is otherwise not modified. The comments have been revised. To see additional references concerning the treatment of the genus, see under the Flora of North America tab. Based on S. Phillips (1995) & T.A. Cope (1995) Plants annual or perennial. Leaves: ligules a line of hairs or ciliate membrane; blades linear to lanceolate. Inflorescences panicles of spikelike branches racemosely attached to the central axes; branches axes usually simple, sometimes the lower branches with secondary branches, axes usually 3-angled or flattened, sometimes winged. Spikelets single or in pairs, loosely or densely attached along the branch axes, plump, usually elliptic; lower glumes varying from small and without veins to many veined and almost equalling the upper floret, the bases sheathing and sometimes extending down into a short stipe; upper glumes equaling the spikelets, membranous or cartilaginous; lower florets male or sterile; lower lemmas similar in length and texture to the upper glumes; upper lemmas crustaceous to coriaceous, striate or rugose, margins inrolled, tips acute to obtuse, entire to mucronate; paleas obtuse to acute, tips enclosed by the lemmas. Caryopses elliptic to subrotund, sometimes strongly flattened. Urochloa has been expanded to included many species that were previously included in Brachiara. Unfortunately, the position of some species of Brachiaria has not yet been determined so the only names available place them in Brachiaria. Once they have been transferred, the number of species formally included in Urochloa is likely to be around 170 or more. It is currently around 160. The Flora of Somalia treats Urochloa as having 3 species in Somaliland and Somalia and Brachiaria as having 16. Because one of the species of Brachiara involved belongs in Moorochloa, this means there are probably about 18 species of Urochloa, as currently interpreted, in Somaliland and Somalia. Key to the species of Urochloa in Somaliland and Somalia. Global distribution of Urochloa. Note: GBIF records include introduced and cultivated plants. Consequently, the distribution shown often differs from statements about a taxon's native distribution.
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