POACEAE. 29 



persistent; lemmas of about the same texture, deciduous, each 

 bearing a dorsal awn, the apex erose-truncate; palea narrow; 

 grain oblong, free, enclosed in the lemma. 



Glumes scarcely equalling the lemma. D. caespilosa. 

 Glumes exceeding the lemma. 



Glume about 4 mm. long. D. elongata. 



Glume about 7 mm. long. D. calycina. 



Deschampsia caespitosa (L.) Beauv. Densely tufted perennial; stems 60- 

 150 cm. high, much exceeding the numerous basal leaves; stem leaves 3, the 

 blades narrow, involute, 5-12 cm. long, scabrous, the smooth sheaths shorter 

 than the internodes; panicle 10-30 cm. long, usually open, the capillary 

 branches in whorls of 2-5, flower-bearing above the middle; spikelets shining, 

 greenish or purplish, 2-3 mm. long; lemma hairy at the base, erose-toothed 

 at the apex, bearing a slender awn near the base. Plentiful in wet ground. 



Deschampsia elongata (Hook.) Munro. Stems densely tufted, smooth, 

 30-90 cm. tall; leaves filiform, commonly involute, smooth; panicle narrow, 

 15-45 cm. long, somewhat nodding; branches very unequal, ascending or 

 appressed, very slender, naked below; spikelets pale green, usually purple- 

 tinged near the apex; lemmas hairy at base, shining, irregularly toothed at 

 apex, bearing a slender awn about twice as long. Common in dry soil. 



Deschampsia calycina Presl. Annual; the slender stems erect, 15-40 cm. 

 tall; leaves narrow, involute, the blades 2-6 cm. long; panicle very loose, 7-20 

 cm. long, with subequal branches mostly in twos, these capillary, branched 

 above and bearing spikelets near the tips; spikelets pale green, sometimes 

 purple-tinged, about 7 mm. long; lemma long-hairy at the base, minutely 

 toothed at the apex, bearing a geniculate awn three or four times as long. 

 Very abundant in dry soil. 



49. TRISETUM. 



Ours all cespitose perennials; inflorescence a spike-like or 

 open panicle; spikelets 2-4-flowered, the flowers all perfect or 

 the uppermost staminate; rachilla glabrous or with long soft 

 hairs, extending beyond the flowers; glumes unequal, acute, 

 persistent; lemmas 2-4, usually shorter than the glumes, decidu- 

 ous, 2-toothed, bearing a dorsal awn below the apex or sometimes 

 awnless; palea narrow, hyaline, 2-toothed; grain free, enclosed 

 in the lemma. 



Lemmas awnless; panicle narrow. T. muticum. 

 Lemmas awned. 



Panicle dense and spike-like; ovary smooth. T. spicatum. 

 Panicle loose and open; ovary hairy at apex. 



Sheaths glabrous; lemma 3-4 mm. long. T. cernuum. 



Sheaths pubescent; lemma 7 mm. long. T. canescens. 



Trisetum muticum (Boland.) Scribn. Stems erect, 30-75 cm. high; 

 blades flat, scabrous or sometimes pubescent; panicles narrow, erect, rather 

 dense; spikelets 2-flowered; glumes subequal, acute; lemmas smooth, awnless 

 or very short awned. A rare grass only known in our limits from near Spangle. 



Trisetum spicatum (L.) Richter. Densely tufted, 10-40 cm. high, pubes- 

 cent to glabrous with the sheaths pubescent; panicle oblong-ovate, 5-15 cm. 



