GRAMINEAE. 12$ 



59. BOUTELOUA Lag. 



Annual or perennial grasses with flat or convolute leaves and numerous spike- 

 lets in few one-sided spikes. Spikelets 1-2 -flowered, arranged in two rows on one 

 side of a flat rachis. the rachilla extended beyond the base of the flowers, bearing 

 1-3 awns and 1-3 rudimentary scales. Two lower scales empty, acute, keeled; 

 flowering scale broader, 3-toothed, the teeth awn-pointed or awned; palet hyaline, 

 entire or 2-toothed. Stamens 3. Styles distinct. Stigmas plumose. Grain 

 oblong, free. [In honor of Claudius Boutelou, a Spanish botanist.] About 30 

 species, particularly numerous in Mexico and in the southwestern U. S. 



Rachilla bearing the rudimentary scales and awns glabrous; second scale strongly 

 papillose-hispid on the keel. i. B. hirsuta. 



Rachilla bearing the rudimentary scales and awns with a tuft of long hairs at the apex ; 

 second scale scabrous and sparingly long-ciliate on the keel. 2. B. oligostachya. 



1. Bouteloua hirsuta Lag. HAIRY MESQUITE-GRASS. (I. F. f. 411.) Culms 

 1.5-5 dm. ta ^> ere ct, simple or sometimes sparingly branched at the base. Sheaths 

 mostly at the base of the culm; leaves 2.5-12.5 cm. long, 2 mm. wide or less, 

 erect or ascending, flat, scabrous, sparingly papillose-hirsute near the base, espe- 

 cially on the margins; spikes 1-4, 1.25-5 cm. long, usually erect or ascending, the 

 rachis extending beyond the spikelets into a conspicuous point; spikelets numerous, 

 5-6 mm. long, pectinately arranged; second scale strongly papillose-hirsute on the 

 keel; third scale pubescent, 3-cleft to the middle, the nerves terminating in awns; 

 rachilla without a tuft of hairs under the rudimentary scales and awns. In dry 

 soil, especially on prairies, 111. to Dak., Tex. and Ariz. July-Sept. 



2. Bouteloua oligostachya (Nutt.) Torr. GRAMA-GRASS. MESQUITE-GRASS. 

 (I. F. f. 412.) Culms 1.5-4.5 dm. tall, erect, simple. Leaves 2.5-10 cm. long, 2 

 mm. wide or less, involute, at least at the long slender tip, smooth or scabrous; 

 spikes 1-3, 2.5-5 cm. long, often strongly curved, the rachis terminating in a short 

 inconspicuous point; spikelets numerous, pectinately arranged, about 6 mm. long; 

 second scale scabrous and sometimes long-ciliate on the keel, sometimes with a 

 few papillae; third scale pubescent, 3-cleft, the nerves terminating in awns; rachilla 

 with a tuft of long hairs under the rudimentary scales and awns. On prairies, 

 Manitoba to Alberta, south to Wis., Tex. and Mex. July-Sept. 



60. ATHEROPOGON Muhl. 



Perennial grasses with narrow flat leaves and an inflorescence composed of nu- 

 merous short scattered few-flowered one-sided spreading or frequently reflexed 

 spikes. Spikelets i -flowered, crowded in 2 rows, sessile, imbricated, the rachilla 

 articulated above the empty scales and extending beyond the flower, its summit 

 bearing scales or awns. Scales 3 or more, the lower 2 empty, unequal, acute, nar- 

 row, keeled, the third scale thicker and broader, enclosing a narrow 2-toothed hya- 

 line palet and a perfect flower, 3-toothed at the apex, the teeth more or less awned; 

 the small upper scales minute, awned. Stamens 3. Styles distinct. Stigmas 

 plumose. Grain free, enclosed in the scale. [Greek, in reference to the awns of 

 the flowering scales.] Species about 15, natives of temperate and tropical regions. 



i. Atheropogon curtipendulus (Michx.) Fourn. RACEMED BOUTELOUA. 

 (I. F. f. 413.) Culms 3-9 dm. tall, erect, simple, smooth and glabrous. Leaves 

 5-30 cm. long, 4 mm. wide or less, flat or involute, rough, especially above; spikes 

 numerous, 6-16 mm. long, widely spreading or reflexed; spikelets 4-12, divergent 

 from the rachis, 7-12 mm. long; scales scabrous, especially on the keel, the first 

 shorter than or equalling the second; the third 3-toothed, the nerves extended into 

 short awns; rachilla bearing at the summit a small awned scale, or sometimes a 

 larger 3-nerved scale, the nerves extended into awns; anthers vermillion or cinna- 

 bar-red. In dry soil, Ont. to Manitoba, south to N. J., Ky., Tex. and Mex. July- 

 Sept. (Bouteloua curtipendula (Michx.) Torr.) 



61. BECKMANNIA Host. 



A tall erect grass with flat leaves and erect spikes borne in a terminal panicle. 

 Spikelets i-2-flowered. glo1>ose. compressed. Scales 3 or 4; the 2 lower empty, 

 membranous, saccate, obtuse or abruptly acute; the flowering scales narrow, thin- 



