In wet meadows, swales, springy places along streams and about pools, damp 

 thickets and wettish low open ground, in N. M. (San Miguel and Socorro cos.) 

 and Ariz. (Cochise Co.); Me. and Que. to Wash., s. to N. C, Ark., N.M. and 

 Ariz. 



12. Muhlenbergia Schreberi J. F. Gmel. Nimblewill muhly. 



Perennial with stolons about 1 mm. thick, freely rooting; flowering culms 1-4 

 dm. long, 0.5-1 mm. thick, weak, ascending; ligule an erose scale about 0.5 mm. 

 long, not auricled; blades 3-8 cm. long, 1-4 mm. broad, weak, flat, diverging 

 from culm at right angles; panicles 5-12 cm. long, 1-3 mm. thick, spikelike but 

 lax and interrupted, weak and nodding; glumes minute, 0.1-0.3 mm. long, muti- 

 cous; lemma about 2 mm. long, linear-lanceolate, with an awn 1.5-6 mm. long; 

 palea about 2 mm. long. 



Moist usually shaded ground near streams and marshy areas, wet meadows 

 and wet sandy-clay about ponds, in Okla. (Waterfall) and e., s.e. and n.-cen. 

 Tex. and e. Edwards Plateau and n. Rio Grande Plains, scattered but locally 

 abundant, spring-fall; e. U.S., w. to Neb., Kan., Okla. and Tex. 



34. Sporobolus R. Br. Dropseed 



Perennials (except in 1 species); inflorescences paniculate, either open and dif- 

 fuse or spiciform; spikelets 1 -flowered, slightly laterally compressed, with mem- 

 branous to scarious parts; rachilla with zone of abscission just above the glume 

 node and below the lemma nodes in most species; palea often splitting at 

 maturity; grain usually falling readily, often reddish, with a coat (ovary wall) 

 that imbibes water, becoming loose and easily detached from the remainder of 

 the grain. 



A genus of about 150 species of the warmer regions of the world. 



1. Mature panicles more than 9 cm. broad 1. S. texanus. 



1. Mature panicles less than 9 cm. broad (2) 



2(1). Collar of sheath (dorsal summit where it joins the blade) abundantly 

 furnished with soft white hairs; panicle more than 2 cm. broad 

 2. S. flexuosus. 



2. Collar of sheath glabrous (but the corners commonly pilose); panicle less 



than 1.5 cm. broad (3) 



3(2). Mature panicles less than 5 cm. long 3. S. virginicus. 



3. Mature panicles more than 5 cm. long 4. S. indicus. 



1. Sporobolus texanus Vasey. Fig. 118. 



Tufted perennial from short very firm rhizomes 1.5-2 mm. thick, or these 

 often apparently absent; aerial culms numerous, 3-7 dm. long, 1-2 mm. thick, 

 leafy; ligule a very dense line of cilia about 0.5 mm. long; blades 1-12 (-20) cm. 

 long, 2-4 mm. broad near the base, flat or drying involute, pointed; summit of 

 sheath glabrous but the corners and margins often sparsely long-pilose; panicle 

 15-30 cm. long, 1-2 dm. broad, vaguely obovoid, open and diffuse, the branches 

 not whorled but bearing numerous somewhat flexuous capillary ultimate branch- 

 lets 5-20 mm. long, each terminating in a single spikelet; first glume 0.7-1.5 mm. 

 long; second glume 2.1-2.8 mm. long; lemma 2.3-2.9 mm. long; palea about 

 equaling lemma. 



Seasonally moist and often subsaline low areas, salt marshes, mesas and valley, 

 in Okla. (Waterfall), the Tex. Plains Country and Trans-Pecos, infrequent or 

 rare, N.M. (Chaves and Eddy cos.) and Ariz. (Coconino Co.), summer-fall; w. 

 Kan. to Tex. and w. to Ariz. 



250 



