342 Bulletin No. 205 [March, 



c. Glumes awned, always considerably longer than the lemma, sometimes 

 nearly twice its length; panicle usually compact, resembling an 

 interrupted spike. M. racevwsa 



cc. Glumes seldom awned, usually not longer than the lemma, but some- 

 times slightly longer; panicles usually slender. 

 d. Glumes always shorter than the lemma, never more than three- 

 fourths its length, broad at base; leaf -blades spreading. 

 e. Lemma awnless or short-awned; spikelets 1.5 to 2 mm. long; 

 nodes not pubescent; culms not densely short pubescent. 



M. sobolifera 

 ce. Lemma long-awned; spikelets 3 to 4 mm. long; nodes pu- 

 bescent; culms densely short pubescent. M. tenuiflora 

 dil. Glumes about equal in length to the lemma, sometimes longer, 

 very narrow at the base ; leaf -blades erect, or nearly so. 

 e. Culms smooth and shiny below the nodes, never covered with 

 fine hairs. M. mexioana 

 ee. Culms with very short, fine hairs for an inch or two below the 

 nodes. 

 f. Callus without hairs. M. gkibriflora 

 ff. Callus with hairs one-third to one-half the length of the 

 lemma, 

 g. Panicles few-flowered; lemma usually long-awned. 



M. umhrosa 

 gg. Panicles densely flowered; lemma not awned. 

 I M. foliosa 



Muhlenbergia capillaris (Jjam.) Trin. 

 Long-awned Hair Grass (Fig. 136) 



Culms growing in tufts, 1.5 to 3 feet tall, usually smooth ; sheaths 

 sm^ooth, short at the base of the plant, and often overlapping, but 

 longer near the summit ; blades 4 to 12 inches long, about 2 mm. wide, 

 usually involute ; panicle spreading, with long, capillary branches, 

 spikelets, excluding the awn, 3.5 to 4 mm. long, on long, capillary 

 pedicels, which are thickened near the base of the spikelet; glumes 

 about half as long as the awned lemma ; awn 5 to 18 mm. long ; callus 

 hairs very short. 



This species is found in dry soil. So far only one specimen has 

 been seen from Illinois. The panicle is usually purple. 



UNION CO. Without locality, Seymour in 1881. 



Muhlenbergia cuspidata (Torr.) Eydb. 

 (Fig. 137) 



Culms in tufts, 1 to 2 feet tall, very slender, smooth ; sheaths and 

 blades smooth; blades 4 to 10 inches long, very narrow, usually in- 

 volute ; panicle very slender, f ew-flov^^ered ; spikelets 3 to 4 mm. long, 

 the glumes with a cusp or short awn about two-thirds as long as the 

 lemma ; callus hairs wanting. 



This species is described in Gray's Manual (seventh edition) as 

 Sporobolus hi'evifolius (Nutt.) Scribn. It is found in dry places. The 



