1 88 



GRAMINEAE. 



VOL. I. 



ii. Muhlenbergia brevifolia (Nutt.) Nash. Short-leaved Rush-grass. Fig. 449. 



Agrostis brevifolia Nutt. Gen. i : 44. 1818. 



Sporobolus Richardsonis Merrill, Rhodora, 4: 46. 1902. 



Sporobolus brevifolius Scribn. Mem. Torr. Club, 5: 39. 1895. 



Smooth and glabrous, culms 6'-i8' tall, arising from a 

 horizontal rootstock, erect, slender, decumbent and branch- 

 ing above. Sheaths much shorter than the internodes; 

 ligule f"-i" long, acutish; blades \'-2' long, involute- 

 setaceous; panicle -3' in length, usually about i, linear, 

 its branches i'-i' long, erect orappressed; spikelets ii"-i4" 

 long, the outer scales unequal, about one-half as long as the 

 third, scabrous on the* keel and at the apex; third scale 

 long-acuminate, sometimes cuspidate, scabrous toward the 

 apex. 



In meadows and along rivers, Anticosti Island and Maine 

 to British Columbia, south in the mountains to New Mexico 

 and California. Summer. 



12. Muhlenbergia cuspidata (Torr.) Nash. Prairie Rush-grass. Fig. 450. 



Vilfa cuspidata Torr. ; Hook. Fl. Bor. Am. 2 : 238. 1840. 

 Sporobolus cuspidatus Wood, Bot. & Fl. 385. 1870. 



Sporobolus brevifolius Scribn. Mem. Torr. Club, 5 : 39. In 

 part. 1894. 



Smooth and glabrous, culms i-2 tall, erect, simple 

 above, branched at the base. Sheaths shorter than the 

 internodes ; ligule a mere ring, ^" long or less, erose-trun- 

 cate ; blades i'-4/ long, less than i" wide at the base, erect, 

 involute-setaceous, at least when dry; panicle ii'-5' in 

 length, slender, its branches i'-i' long, appressed; spike- 

 lets ii"-ii" long, the outer scales half .to three-quarters 

 as long, acuminate or cuspidate, scabrous on the keel ; 

 third scale long-acuminate and cuspidate, sparingly 

 scabrous. 



In dry soil, Manitoba to Alberta, south to Missouri and 

 Kansas. Aug.-Sept. 



13. Muhlenbergia gracillima Torr. Filiform Dropseed. Fig. 451. 



M. gracillima Torr. Pac. R. R. Rept. 4: 155. 1875. 



Glabrous, culms 4'-i4' tall, from a slender creeping 

 rootstock, erect, slender, simple, rigid. Sheaths smooth; 

 ligule i"-2" long, entire and acuminate, or variously 

 cleft, with acuminate teeth; blades i'-2' long, involute- 

 setaceous, smooth or somewhat scabrous, rigid, the 

 basal numerous, usually strongly recurved, the 1-3 culm 

 blades erect or ascending; panicle 2'-o/ in length, open, 

 the branches finally widely spreading, i'~3' long, fili- 

 form; spikelets about as long as the filiform pedicels 

 which are clavate-thickencd at the apex ; outer scales 

 unequal, usually awn-pointed or short-awned, slightly 

 scabrous; third scale ii"-ii" long, longer than the 

 outer ones, sometimes twice as long, scabrous ; awn 

 i "-2" long. 



On prairies, Kansas to Colorado, south to Texas and 

 Arizona. Sept.-Oct. 



