GENERA OF GRASSES OF THE UNITED STATES. 



109 



drooping branches, the florets distant in the usually 3-flowered spike- 

 lets. Trisetum pennsylvanicum (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 

 spicatum constitutes an important part of the forage on alpine slopes. 



