170 GRAMINEAE. 
2. Deschampsia flexudsa (L.) Trin. Wavy Hair-grass. (Fig. 388.) 
Aira flexuosa I,. Sp. Pl. 65. 1753. 
Deschampsia flexuosa Trin. Bull. Acad. Sci. St. 
Petersb. 1:66. 1836. 
Glabrous throughout, culms 1°-2'%° tall, erect, 
slender, simple, smooth. Sheaths much shorter 
than the intertodes; ligule 1’ long or less; 
leaves involute-setaceous, smooth beneath, scab- 
rous above, the basal very numerous, one-fifth 
the length of the culm or less, those of the culm 
1/-3/ long; panicle open, 2/’-8’ in length, the 
branches ascending or erect, sometimes widely 
speading, naked at the base, flexuous, the lower 
113’-5’ long; spikelets 214’/-214’” long; flow- 
ering scales about 2’” long, acutely toothed at 
the apex; awns bent and twisted, much ex- 
ceeding the scale; upper scale reaching to or 
extending beyond the apices of the empty ones, 
In dry soil, Greenland and Newfoundland to On- 
tario and Michigan, south to North Carolina and 
Tennessee. Ascends to 5100 ft. in the Adirondacks. 
Alsoin Europe. July-Aug. 
3. Deschampsia atropurptrea (Wahl.) Scheele. Mountain Hair-grass. 
(Fig. 389.) 
Aira atropurpurea Wahl. F1. Lapp. 37. 1812. 
Deschampsia atropurpurea Scheele, Flora, 27: 56. 
1844. 
Glabrous and smooth or very nearly so, culms 
6-18’ tall, erect, simple, rigid. Sheaths shorter 
than the internodes; ligule 1’’ long or less, trun- 
cate; leaves 1//-2/’ wide, erect, sometimes slightly 
scabrous above, the basal 2%s’—5’ long, those of the 
culm shorter; panicle contracted, usually purple or 
purplish, 1/-2’ in length, the branches erect, or 
sometimes ascending, the lower '%/’-1'%’ long; 
spikelets 214’” long; flowering scales about 11¢// 
long, erose-truncate at the apex; awns bent and 
much longer than the scales; upper scale much 
exceeded by the very acute outer ones. 
On alpine summits of New York, New England, 
Montana, Oregon and Washington, north to Labrador 
and Alaska. Alsoin Europe. July—Aug. 
43. TRISETUM Pers. Syn. I: 97. 1805. 
Mostly perennial tufted grasses, with flat leaves and spike-like or open panicles. Spike- 
lets 2-4-flowered, the flowers all perfect, or the uppermost staminate; rachilla glabrous or 
pilose, extended beyond the flowers. Scales 4-6, membranous, the 2 lower empty, unequal, 
acute, persistent; flowering scales usually shorter than the empty ones, deciduous, 2-toothed, 
bearing a dorsal awn below the apex, or the lower one sometimes awnless. Palet narrow, 
hyaline, 2-toothed. Stamens 3. Stylesdistinct. Stigmas plumose. Grain free, enclosed in 
the scale. [Latin, referring to the three bristles (one awn and two sharp teeth) of the flow- 
ering scales in some species. ] 
_ About 50 species, widely distributed in temperate or mountainous regions. Besides the follow- 
ing, about 8 others occur in the western parts of North America. 
Flowering scales all bearing long dorsal awns. 
Panicle contracted, dense; flowering scales 2's"’ long or less. 1. 7. subspicatum. 
Panicle open, loose; flowering scales 2's'’ long or more. 2. T. flavescens. 
Lower flowering scale not bearing a long dorsal awn, a rudiment sometimes present. 
3. T. Pennsylvanicum. 
