1918] The Grasses of Illinois 379 



ILLINOIS SPECIMENS: Without locality, southern Illinois, Vasey. adams co. 

 Quincy, Bebb, July, 1860. cass CO. Chandlerville, Seymour, Aug., 1886. chris- 

 tian CO. Taj'lorville, Andrews. Henderson co. Oquawka, Patterson, jackson 

 CO. Carbondale, Seymour, Aug., 1880. jersey co. Grafton, Seymour, peoria 

 CO. Peoria, Brendel; Peoria, McDonald, Aug., 1895 and Sept., 1903. st. clair 

 CO. Without locality, Eggert, Sept., 1886; Mascoutah, Welsch. union co. Cob- 

 den, Seymour, Aug., 1880. wabash co. Without locality, Shearer. 



48. TRIPLASIS Beauv. 



These grasses are perennials with small panicles of 2- to 6-flowered 

 spikelets which have the three nerves of the lemma, as well as the palea, 

 densely hairy. The glumes are unequal and keeled, the lemmas are 

 toothed at the end, somewhat like Tridens. The leaves are long, very 

 narrow, and usually involute. The ligule is a fringe of hairs 1 to 2 mm. 

 long. 



Triplasis purpurea (Walt.) Champ. 

 Sand Grass (Figs. 210 and 211) 



Trieuspis purpurea, Patterson '76, 50; Flagg '78, 281. Triplasis purpurea, 

 Brendel '87, 88. Tricuspis purpurea, Gleason '10, 149. 



Culms in tufts 1 to 2 feet high, smooth ; sheaths loose, shorter than 

 the internodes ; blades small, rough on the upper surface, 1 to 3 inches 

 long, not over 3 mm. wide, usually involute; panicles 1 to 3 inches 

 long, usually purplish, late in the season inclosed in the upper sheaths ; 

 spikelets 5 to 8 mm. long, the awn of the lemma very short. 



This grass is most abundant in sandy places, being first reported 

 in Illinois from sandy prairies and barrens. 



ILLINOIS SPECIMENS: Without locality, Vasey. cass co. Beardstown, Mc- 

 Donald, Sept., 1901. HENDERSON CO. Oquawka, Patterson, Sept., 1872. mason 

 CO. Without locality. Wolf, wabash co. Hanging Eock, SchnecTc, Oct., 1900; 

 Mt. Cartnel, SchnecTc, Oct., 1876. 



49. ERAGROSTIS Beauv. 



These grasses vary considerably in habit. There are both annual 

 and perennial species. The panicles are composed of 2- to many-flow- 

 ered spikelets. The glumes are keeled and shorter than the florets. The 

 leaves are generally flat and narrow ; the ligule is composed of a row 

 of hairs. Owing to the great variation in the number of florets in a 

 spikelet, the same species may present a very different appearance 

 under different conditions and at different seasons of the year. 

 Eragrostis liypnoides is dioecious ; the lemmas of the pistillate flowers 

 are always slightly narrower and more pointed than those of the 

 staminate. The lemmas of many species fall with the grain when it is 

 ripe, leaving the paleas attached to the rachilla. 



a. Culms erect or ascending, not creeping along the ground and rooting at the 



nodes, 

 b. Spikelets usually less than 5-flowered, 2 to 3 mm. long. 



