10 



CONTRIBUTTOISrS FEOM THE NATIONAL HEEBARIUM. 



Plants less densely tufted; leaves flat, green^ membranaceous. 

 Lemma indurated, not at all keeled. 



Spikeletis 5 to lO-fiowered; lemma awnleBs or rarely short 



awned. 

 Spikeleta 3 to 6-flowered; lemma awnless. 



Glumes scarious-margined, much shorter than the 

 lemma; lemma not acuminate. 

 Lemma acute; spikelets loosely scattered. 



23. elatior. 



24. obtusa. 



Lemma obtuse; spikelets somewhat ajjrgregated. 25. shortii. 

 Glumes "without scarious margins, nearly as long as 



the lemma; lemma acuminate. 



Spikelets j^laucouis, loosely 4 to 6-flowered; lemma 



often with a short awn; sheaths smooth. 

 Spikelets green, closely 2 to 3-flowered; empty 

 glumes scabrous; sheaths short-pubescent. 

 Lemma awned, membranaceous, Indurated only near the base 

 and keeled at least above the midrlle. 



Floret long-stipitate at base; awn terminal. 

 Floret ]iot stipitate at base. 



Lemma plainly 5-nerved; awn from a cleft apex. 

 Spikelets 5 to 9 mm. long, 2 to 4-flowered. 



Panicle branches ciliate; awn f^horter than 



the lemma. 

 Panicle branches not ciliate; awn as long or 

 longer than tlie lemma. 

 Spikelets 10 to 15 mm. long, 8 to 7-flowered. 

 Lemma 5-nerved, the intermediate nerves very ob- 

 scure; awn terminal. 



Awn much shorter than the lemma. 

 Awn as long as or longer than the lemma. 



Subgenus TIesperochloa. Perennials, densely tufted but ])ro- 

 du(*ing occasional stout extravaginal scaly stolons; leaf blades 

 broad, iUit, or rarely involute; stamens 3, protru<ling; stigmas 

 elongate, the numerous short mostly simple branches arising from 



all sides. 



A single species. 



26. rermta. 



27. johnsouL 



28. suhuUj^ora 



29, dmyclada 



30. elmerL 

 3L gigantea 



32. fnUercula 



33. suhulala. 



34. confirm 



Subgenus I. Vtjlplv (Gmel.) Hack. 



Vidplti Ginel. FL Bad. 1: 8. 1805, as genus. 



1 u^p/aHack. in Engl. & Prantl, Nat. Pfianzenfam. 2^: 75. 1887, as subgenus. 



Annuals; stamens usually only 1, sometimes 3; florets usually remaining unopened, 

 and consequently self -pollinated; joints of the rachilla usually clavate; stigmas plu- 



1 



mose, the branches toothed, bilateral. 



Many of the specries in this subgenus present slight but remarkably constant differ- 

 ences. In all probability this fact is connected with their close pollination. 



