27 



* * Panicle loose, interrupted; brandtes more or less elongated. 



t Branches densely floicered. 



X Seta' hath antrorsely and retrorsely scabrous. 



17. CH-ffiTOCHLOA ONURUS (Griseb.) n. comb. Setaria onurus Griseb. Fl. 

 Brit. "W. Ind. 555 (1864). Panicum onurum Willd. in Herb., ex Griseb. 



A stout, erect, glabrous perennial, 2 to 10 dm. high, with virgate, interrupted panicles 

 and linear-lanceolate leaves, 1.5 to 4 dm. long. Culms glabrous, erect, simple or 

 sparingly branched at the base, cylindrical; nodes glabrous; sheaths compressed, 

 strigose-pubescent, sometimes slightly scabrous on the keel, the lower ones much 

 longer than the internodes, imbricate, ciliate on the margms, bearded at the 

 apex; ligule short, ciliate; leaf-blades 10 to 15 mm. wide, scabrous on both sides 

 and on the cartilaginous margins, long-acuminate at the apex, tapering at the 

 base, midvein prominent throughout. Panicle loose, cylindrical, 1 to 2 dm. long, 

 1.5 to 2 em. in diameter; rachis striate, pilose; branches spreading-erect, the 

 lower 1.5 to 2 cm. in length, scabrous, equaling or exceeding their internodes; 

 setae mostly solitary, rarely 2 or 3 at each spikelet, slender, flexuous, 1.5 to 2 cm. 

 long, both antrorsely and retrorsely scabrous. Spikelets ovate-globose, acute, 2 

 mm. long; first glume one-third as long as the spikelet, triangular-cordate, acute, 

 abruptly apiculate, 5-nerved; second glume one-half to two-thirds as long as the 

 spikelet, broadly ovate, obtuse or truncate, apiculate, 9 to 11 nerved; third glume 

 equaling the flowering glume, thin, 9-nerved, subtending an ovate hyaline palea 

 nearly its own length; flowering glume ovate-globose, acute, generally abruptly 

 apiculate, transversely undulate-striate below, smooth near the apex. Palea 

 similar in markings, strongly convex. 



West Indies, Mexico, South America. 



Specdiens examined. — Jamaica: March, spikelets from specimens cited byGrisebach 

 (Fl. Brit. W. Ind. 555) sent from Kew Herbarium, also specimen in the Gray 

 Herbarium. Cidia: 3474 Wright 1860, 1864, 3887 Wright 1865; Cienguita, 264 

 Combs 1895. 



In habit very much resembling C. macrostachya, but readily distinguished from this 

 and other related forms by its 9 to 11 nerved second glume and both antrorsely 

 and retrorsely scabrous setee. 



tt Setse antrorsely scabrous only. 

 § Leaves linear, glaucous. 



18. Chaetocliloa composita (H. B. K.) Scribn. U. S. Dept. Agr., Div. Agros. Bui. 

 4: 39 (1897). Setaria composita H. B. K. Nov. Gen. & Sp. PI. 1: ill (1815). 

 (Fig. 15.) 



A pale, glaucous, csespitose perennial, 3 to 10 dm. high, much branched from the 

 base, with long, linear leaves and cylindrical, dense, or more or less interrupted 

 spike-like panicles 5 to 16 cm. long, 6 to 15 mm. in diameter, exclusive of the 

 setse. Culms geniculate at the base, subcompressed, scabrous and often pubes- 

 cent, especially below the nodes, rarely glabrous, the innovations usually short 

 and sterile; nodes bearded with a ring of silky, appressed hairs; sheaths striate, 

 compressed, slightly scabrous on the keel above, and pilose at the apex, 

 otherwise glabrous, the lower sometimes pubescent, mostly shorter than the 

 internodes, cihate on the margins; ligule very short, densely ciliate-f ringed 

 with silky hairs 1.5 to 3 mm. long; leaf-blades linear, plane, 1 to 2.5 dm. long, 2 

 to 5 mm. wide, glaucous, long, narrow, acuminate at the apex, scabrous on both 

 sides or sometimes nearly glabrous, midvein prominent below, obscure above. 

 Panicle pale green; rachis angular, striate, pilose; branches short, densely 

 flowered, contiguous, crowded or sometimes rather remote, especially below; 

 setse single, rarely in pairs, green, flexuous, 5 to 15 mm. long, antrorsely scabrous. 



