426 POACEiE. 



the plains and mesas after the rainy season; less abundant and of 

 less utility than B. pohjdacliya Torr. var. major. Yasey. 



19. B. uniflora Yasey, Coult. Bot. Gaz. 16: 26 (1891). 



A slender perennial, 30-10 cm. high. Leaves of the culm 4, 

 sheaths shorter than the internodes; ligule a ring of short hairs; 

 blades rigid, becoming involute, 8-15 cm. long, 1.5-2 mm. wide. 

 Panicle included at the base, racemose, 8-12 cm. long, bearing 35- 

 50 spikes. Spikes 7-8 mm. long, 1-flowered, rachis linear, 1-6 mm. 

 long; empty glumes conduplicate, 1-nerved, first linear, 3-4 mm. 

 long; floral glume 5-6 mm. long; palea 4-5 mm. long, usually a 

 capillary pedicel present. 



Texas, Nedhif in 1890. 



20. B. Triathera Benth. Journ. Linn. Soc. 19:104 (1882). 

 Trimia racemosa H. B. K. Nov. Gen. et Sp. 1:178 (1815). 

 Atheropogon Tricena Spreng. Syst. 1:293 (1824). 



A slender tufted perennial, 30-40 cm. high. Ligule a fringe 

 of hairs; blades of sterile shoots involute, 6-12 cm. long, those of 

 the culm shorter, about 2 mm. wide. Panicle racemose, 8-12 cm. 

 long, bearing 35-50 spikes. Spikes 6 mm. long, 1-flowered, rachis 

 bristlelike, 2 mm. long, empty glumes linear, conduplicate, 1-nerved, 

 first 2 mm. long, second 4.5 mm. long; floral glume 5-6 mm. long, 

 palea but little shorter; rudiment 3-4 mm. long, with 3 awns 8-10 

 mm. long. 



Mexico, Pr ingle 4782. 



21. B. Texana S. Wats. Proc. Am. Acad. 18: 196 (1883). 



A densely tufted glabrous or sparingly villous perennial. Culms 

 erect or geniculate, 20-30 cm. high. Blades flat or involute, tliinly 

 pubescent on the upper surface, the lower blades 6-18 cm. long. 

 Spikes 5-10, secund, cuneate, 1-1.5 cm. long, including the setse, 

 borne on an axis 4-5 cm. long. Spikelets 4-6, crowded on the very 

 short hairy rachis, first glume lanceolate, 2 mm. long, with a seta 

 half as long, second ovate-lanceolate, pubescent on the back, 3-5 

 mm. long, bifid, the strong midnerve produced into an awn about 



2 mm. long; floral glume elliptical-ovate, about 4 mm. long, with 



3 nearly equal setae reaching above the apex about 1 mm. ; a mem- 

 branous tooth on each side of the middle seta; palea as long and as- 



