i8o 



GRAMINEAE. 



x. Bouteloua hirsuta Lag. Hairy Mesquite-grass. (Fig. 411.) 



Bouteloua hirsuta Lag. Var. Cienc. y Litter. 2: Part 4, 



141. 1805. 



Culms 6 / -2o / tall, erect, simple or sometimes 

 sparingly branched at the base, smooth and gla- 

 brous. Sheaths mostly at the base of the culm, 

 the lower short and crowded, the upper longer; lig- 

 ule a ring of short hairs; leaves \ r -$ f long, \" wide 

 or less, erect or ascending, flat, scabrous, spar- 

 ingly papillose-hirsute near the base, especially on 

 the margins; spikes 1-4, J^'-a' long, usually erect 

 or ascending, the rachis extending beyond the 

 spikelets into a conspicuous point; spikelets nu- 

 merous, 1%"-$" long, pectinately arranged; first 

 scale hyaline, shorter than the membranous second 

 one, which is 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, Illinois to Dakota, Texas and Arizona. July-Sept. 



2. Bouteloua oligostachya (Nutt. ) Torr. Grama-grass. Mesquite-grass. 



(Fig. 412.) 



Atheropogon oligostachyus Nutt. Gen. i: 78. 1818. 

 Bouteloua oligostachya Torr.; A. Gray, Man. Ed. 2, 553. 



1856. 



Culms 6 / -i8 / tall, erect, simple, smooth and gla- 

 brous. Sheaths shorter than the internodes; ligule a 

 ring of short hairs; leaves \'-^ f long, i" wide or less, 

 involute, at least at the long slender tip, smooth or 

 scabrous; spikes 1-3, i'-2' long, often strongly curved, 

 the rachis terminating in a short inconspicuous point; 

 spikelets numerous, pectinately arranged, about $ ff 

 long; first scale hyaline, shorter than the membranous 

 second one, which is scabrous and sometimes long- 

 ciliate on the keel, and sometimes bears a few papillae; 

 third scale pubescent, 3-cleft, the nerves terminating in 

 awns; rachilla with a tuft of long hairs under the rudi- 

 mentary scales and awns. 



On prairies, Manitoba to Alberta, south to Wisconsin, 

 Texas and Mexico. July-Sept. 



3. Bouteloua curtipendula (Michx.) Torr. Racemed Bouteloua. (Fig. 413.) 



Chloris curtipendula Michx. Fl. Bor. Am. i: 59. 1803. 

 Bouteloua racemosa Lag. Var. Cienc. y Litter. 2: Part 



4, 141. 1805. 



Bouteloua curtipendula Torr. Emory's Rep. 153. 1848. 

 Bouteloua curtipendula var. aristosa A. Gray, Man. 



Ed. 2, 553. 1856. 



Culms i-3 tall, erect, simple, smooth and gla- 

 brous. Sheaths shorter than the internodes; ligule 

 a ring of short hairs; leaves 2 / -i2 / long, i" wide 

 or less, flat or involute, rough, especially above; 

 spikes numerous, $"-$>" long, widely spreading or 

 reflexed; spikelets 4-12, divergent from the rachis, 

 3/4 "-5" 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 cinnabar-red. 

 In dry soil, Ontario to Manitoba, south to New Jersey, Kentucky, Texas and Mexico. July-Sept. 





