Class III. Order III. 31 



33. ARISTIDA. 

 ARISTIDA DICHOTOMA. J\lx. Forked Aristida. 



Cespitose ; culms dichotomous ; flowers subspiked ; 

 lateral awns very short, the intermediate one con- 

 torted. 



A slender grass with short, lateral branches and setaceous 

 leaves. Spikes or racemes slender, with twisted awns. 



Road sides in gravelly soils. September. 



34. STIPA. 



STIPA AVENACEA. L. Feather grass. 



Leaves striated, smooth ; panicle spreading some- 

 what one sided, its branches verticillate ; calyx as 

 long as the seed ; awn naked, finally contorted. 



Remarkable for the length of its awns. Culm two or three 

 feet high, slender, naked above. Leaves narrow, smooth below, 

 inclining to roll up. Panicle long, few-flowered, nodding when 

 young. Glumes of the calyx nearly equal, acuminate. Corolla 

 stipitate, its lower valve terminating in a twisted awn tw"o or 

 three inches long, at first straight, but at length contorted. Seed 

 a third of an inch long. Dry woody hills near the Andover 

 turnpike, Medford. June, July. Perennial. 



35. AIRA. 

 AIRA FLEXUOSA. L. WooA Hair grass. 



Panicle spreading, trichotomous ; peduncles flex- 

 uous, awns geniculate ; leaves setaceous, culm near- 

 ly naked. 



A tall thin grass found in old woods, one or two feet high. 

 Glumes membranaceous, purplish. Corolla with a bent awn neaj 1 

 the base. Sides of Wachusett hill, June. 



AIRA TRUNCATA. Muld. Truncate Hair grass. 



Panicle oblong, racemose ; calyx unequal, three 

 flowered, one abortive ; lower glume obtuse, corolla 

 glabrous. 



