GENERA OF GRASSES OF THE UNITED STATES. 
109 
drooping branches, the florets distant in the usually 3-flowered spike- 
lets. Trisetuiripennsylvanicum (L.) Roem. and Schult. ^Sphenopholis 
palustris (Michx.) 
Scribn.), T. hallii 
Scribn., and T. inter- 
ruptum Buckl. have 
been referred to 
Sphenopholis. I n 
the first, the upper 
lemma is slightly 
bearded at base, the 
lower glabrous ; in 
the other two, the 
lemmas are glabrous. 
In these three species 
the articulation is be- 
low the spikelet, as in 
Sphenopholis, for 
which reason Scrib- 
ner placed them in 
that genus, but their 
a w n e d, relatively 
thin lemmas and 
their glumes alike in 
shape place them 
more naturally in 
Trisetum. 
Fig. 56. — Trisetum spicatum. Plant, x I ; spikelet and floret, X 5. 
The species of Trisetum are all valuable for grazing. Trisetum 
tpicatum constitutes an important part of the forage on alpine slopes. 
