142 Rhodora [August 



and in tlie lemmas and paleas, the latter being always hyaline and 

 strongly narrowed towards the base, and especially is there a common 

 resemblance in the characters of the caryopsis. While the glumes 

 and first floret are persistent, the second floret readily falls off at 

 early maturity and so pronounced is this character that species have 

 been described from herbarium material as having one-flowered spike- 

 lets. Kunth describes thus Reboulea (/racili.'i. 



The characters of the genus SphenopJwli.<i as here constituted are 

 the same as those assigned to Eatonia by Entllicher, Bentham and 

 others excepting those of the lemmas or flowering glumes which are 

 either awnless or awned below the entire or two-toothed apex, awn 

 straight or divergent rarely twisted and geniculate. As here presented 

 the genus stands, as follows: 



Sphenopholis, new name. I 



Reboulea Kunth. Rev. Gram. 1:341, PI. 84, 1S30, not Reboulea 



Raddi 1S20. 

 Cohbauflni.9 Trin (as a Sect. Trisetum.) 1830. Spach as a genus. 



Suites, Butt". 13:1()3, 1S4G, not Bard. 1830. 

 Eatonia Rafin.; EncU. Gen. PI. 99, 1837, not Rafinesque, 1819. 

 (ten. Char.: Spikelets small, 2-3-flowered, paniculate; rhachilla 

 continued above the upper floret into a slender naked or pilose stipe, 

 articulated between the florets and below the spikelets; flowers 

 hermaphrodite. Glumes 2, dissimilar, persistent, membranaceous, 

 the second becoming chartaceous or subcoriaceous in fruit, the first 

 narrow 1- or rarely 3-nerved, the second much broader, usually 

 broadly obovate, 3- or rarely 5-nerved; lemmas rather rigid, char- 

 taceous, 3- rarely 5-nerved, nerves obscure, rounded on the back below 

 compressed near the apex, obtuse, acuminate, entire or 2-toothed, 

 awnless or awned just below the apex; awn straight or divergent, 

 rarely twisted anfl geniculate; palea hyaline, shorter than the lemmas, 

 narrowed towards the base, 2-nerved, usually somewhat 2-lobed and 

 2-toothed at the apex. Stamens 3. Styles very short; stigmas 

 plumose. Caryopsis linear or oblong, more or less compressed, 

 abruptly narrowed above into a short beak, glabrous, exsulcate, loosely 

 enclosed within the rigid fruiting glume, free. 



Slender grasses with usually flat leaves and narrow, often densely 

 flowered panicles. 



Allied to Tri.s-etum. I 



Species 7. All North American. Type, Sphenopholis obtusafa 

 (Aira obiusaia Michx.). 



