744 GRAMINE® AVENA 
TRISETUM 
smooth except the ring of stiff white hairs at the base, and the scabrous 
apex. In cultivated fields and waste places: naturalized from Europe. 
A. Smithii Porter, Gray Man. ed. 3, 640. Stems 2-5 feet high, erect, 
simple, scabrous: sheaths shorter than the internodes, very rough: ligules 
2 lines long: leaves 4-8 inches long, 3-6 lines wide, scabrous: panicle 6-12 
inches long, the branches finally spreading: spikelets 3-6-flowered : empty 
glumes smooth, the second 3-4 lines long, 3-nerved: flowering glumes 5 
lines long, naked at base, strongly nerved, scabrous, bearing an awn 4-4 
their length. Eastern Washington to Michigan. 
28 TRISETUM Pers. Syn. i, 97. (1805.) 
Mostly perennial tufted grasses with flat leaves and spike-like 
or open panicles. Spikelets 2—4-flowered, the flowers all perfect 
or the uppermost staminate. Rachella glabrous or pilose, exten- 
ded beyond the flowers. Glumes 4-6, membranous, the two 
lower empty, unequal, acute, persistent. Flowering glume usu- 
ally shorter than the empty ones, deciduous, 2-toothed, bearing 
a dorsal awn below the apex, or the lower one sometimes awn- 
less. Palet narrow, hyaline, 2-toothed. Stamens 3. Styles dis- 
tinct. Stigmas plumose. Grain free, enclosed in the glume. 
T. barbatum Steud. Svn. Pl. Gram. 229. Stems erect, or decumbent 
at base, often branched below, smooth, leafy nearly to the panicle, 1-3 feet 
high: sheaths sparsely retrorsely hispid, half open above, shorter than 
the internodes: ligules obtuse, erose, 1 line or less long: leaves 3-6 inches 
long, 2-3 lines wide, scabrous, sparsely pubescent or nearly smooth: pani- 
cle open to constricted, 4-8 inches long, its branches 3 inches long or less: 
spikelets rotggns 3-6-flowered, 7-10 lines long; first empty glume very nar- 
rowly ovate, subulate-acute, smooth except the slightly hispid prominent 
keel, 3-4 lines long; second one lanceolate, acute, 5-6 lines long: flowering 
lumes lanceolate, with 2 teeth about 4% line long, pubescent, 5-7 lines 
ong: awn inserted at the base of the sinus bent, hispid and twisted below: 
palet linear thin. Washington to California. 
T. canescens Buckley Proc. Acad. Phil. 1862, 100. Stems erect, 
nearly smooth, 2-3 feet high: sheaths open above, canescent to nearly 
smooth, shorter than the internodes: ligules ovate, erose or lacerate, 2-3 
lines long: leaves flat, 4-10 inches long, 3-4 lines wide, canescent to nearly 
smooth: panicle narrow, 6-8 inches long, its branches unequal, 2 inches 
or less long, erect: spikelets slightly compressed, 3-4 lines long, 2-flowered 
or with only 1 imperfect one: first empty glume narrowly ovate, acute, 
slightly carinate, thin, hispid on the keel, 144-2 lines long; second one 
broadly lanceolate, acute, about 3 lines long: flowering glume ovate-lanceo- 
late, cleft 4% way from the apex, minutely scabrous, 3 lines long: awn 
attached at the base of the cleft, hispid, twisted and bent. Common in 
wooded districts, California to Alaska. 
T. cernuum Trin. Mem. Acad. St. Petersb. 1830, i, 61. Stems slen- 
der, erect, smooth, 2-3 feet high: sheaths loose, open above, smooth or 
scabrous above, shorter than the internodes: ligules ovate, lacerate: 1-6 
lines long: leaves flat, scabrous on both sides or nearly smooth beneath, 
5-10 inches long, 3-6 lines wide: panicle rather loose, nodding, 5-8 inches 
long, its branches slender, ascending: spikelets 2-4-flowered, 3-4 lines long: 
first empty glume narrowly ovate, carinate 1-144 lines long; second one 
broadly oblong, obtuse or acuminate, thin, hispid on the keel above, 
3-nerved below, 2-234 lines long: awn arising below the base, of the cleft, 
3-5 lines long. Along streams in the mountains, California to Alaska. 
T. subspicatum Beauv. Agrost. 180. Softly pubescent to glabrous: 
