POACEAE 129 
70. DESCHAMPSIA Beauv. 
Perennial grasses, with narrow convolute or flat leaf-blades and terminal contracted or 
open panicles. Spikelets 2-flowered, the rachilla articulated above the empty scales and pro- 
longed beyond the flowers. Scales 4, the 2 outer empty, persistent, keeled, acute, mem- 
branous, usually somewhat shining, the flowering scales thin-membranous, almost hyaline, 
entire or toothed, acute, obtuse, or truncate and denticulate at the apex, each bearing a 
slender dorsal straight or geniculate awn which is twisted at the base ; palet narrow, 2- 
nerved. Stamens 3. Styles distinct. Stigmas plumose. Harr GRASS. 
Flowering scales about 2.5 mm. long, erose-truncate: leaf-blades flat. 1. D. caespitosa. 
Flowering scales about 4 mm. long, acute or obtuse : leaf-blades involute. 2. D. flexuosa, 
1. Deschampsia caespitósa (L.) Beauv. Stems tufted, 6-12 dm. tall, erect: leaf- 
blades flat, 2-3 mm. wide, rough above, the basal ones numerous, 1-1 as long as the stem, 
those on the stem 5-15 em. long: panicle open, 7-23 em. long, its branches spreading or 
ascending, naked at the base: spikelets 3.5-4 mm. long, the flowering scales about 2.5 mm. 
long, erose-truncate at theapex, the awns somewhat shorter or a little longer than the scale. 
In wet soil, Newfoundland to Alaska, New Jersey, Illinois, Minnesota and in the mountains to 
North Carolina, New Mexico and California. Also in Europe and Asia. Summer. 
2. Deschampsia flexuósa (L.) Trin. Stems tufted, 3-8 dm. tall, erect, slender: 
leaf-blades involute-setaceous, rough above, the basal very numerous, } as long as the stem 
or less, those on the stem 2-8 cm. long: panicle open, 5-20 em. long, the branches spread- 
ing to nearly erect, naked at the base, flexuous: spikelets 4.5-5 mm. long, the flowering 
scales about 4 mm. long, acutely toothed at the apex, the awns bent and twisted, much ex- 
ceeding the scale. 
In dry soil, Greenland and Newfoundland to Ontario, Michigan, North Carolina and Tennessee. 
Also in Europe. Summer. 
71. TRISETUM Pers. 
Annual or perennial tufted grasses, with flat leaf-blades and terminal spike-like con- 
tracted or open panicles. Spikelets usually 2-flowered, rarely 3-6-flowered, the flowers 
perfect, or the upper one staminate, the rachilla glabrous or pilose, articulated between 
the flowering scales and prolonged beyond them. Scales 4, rarely 5-8, keeled, the 2 outer 
empty, membranous, unequal, acute, entire at the apex, awnless, persistent, the flowering 
scales usually shorter, sometimes longer, 2-toothed at the apex, the teeth acuminate and 
often terminating in a bristle or slender awn, awned, or the lower flowering scale rarely 
awnless, the awn often twisted, inserted below the apex and arising between the teeth ; palet 
hyaline, 2-toothed. Stamens 3. Styles distinct. Stigmas plumose. FALsE OAT. 
Flowering scales each bearing a long awn. 
Empty scales shining, 1-nerved, or the second one 3-nerved. ; 
Panicle spike-like, dense, its branches short and appressed. ; 1. T. subspicatum. 
Panicle loose and open, its branches long and slender, erect or ascending. 2. T. flavescens. 
Empty scales not shining, very strongly nerved, the first 3-nerved, the second 
5-nerved. 
Awn of the flowering scales inserted about 14 way below the apex: teeth 5 
of the flowering scales euneate. 3. T. Hallii. 
Awn of the flowering scales inserted about the middle : teeth of the flower- j 
ing scales subulate. 4. T. interruptum. 
Lower flowering scale not bearing a long awn, a remnant sometimes present. 
Second empty scale less than 3 mm. long : awn of the flowering scales 1-2 mm. i 
long. : 5. T. aristatum. 
Second empty scale 4-5 mm. long: awn of the flowering scales exceeding 3 
mm. in length. 
Empty scales dissimilar, the first much narrower than the second, 1-nerved, 
or sometimes 3-nerved at the base: leaf-blades 1 dm. long or less. 6. T. Pennsylvanicum. 
Empty scales similar, the first about as broad as the second, strongly 3- de 
nerved : leaf-blades 1.5-2 dm. long. 7. T. Ludovicianum. 
1. Trisetum subspicatum (L.) Beauv. Softly pubescent or glabrous in some or all 
of its parts. Stems 1-6 dm. tall, erect: leaf-blades 2-10 cm. long, 1-4 mm. wide: pan- 
icle spike-like, 2-13 cm. long, oval to oblong, sometimes interrupted below : spikelets 2-3- 
flowered, the empty scales hispidulous on the keel, the second one about 5 mm. long, the 
flowering scales 4-5 mm. long, acuminate, hispidulous, each bearing a long bent and some- 
what twisted awn.  [ T. molle Kunth. ] 
In dry or rocky places, Labrador to Alaska, and in the mountains to North Carolina, New Mexico 
and California. Also in Europe and Asia. Summer and fall. 
2. Trisetum flavéscens (L.) R. & S. Stems 4-8 dm. tall, erect, glabrous: leaf- 
sheaths pubescent ; blades 4-13 cm. long, 2-6 mm. wide, rough : panicle open, 5-13 cm. 
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