164 DIAREHENA. — DACTYLIS. 



27. DIARRHEJSTA— Raf. Diaerhexa. 



GENERIC CHARACTER. 



Spikelets several-flowered, smootli and shining, one 

 •one or two of the uppermost flowers sterile. Glumes 

 ovate, much shorter than the flowors, coriaceous, the 

 lower one much smaller. Lower palet ovate, convex 

 on the back, rigidly coriaceous, its 3 nerves termina- 

 ting in a strong and abrupt cuspidate or awl-shaped 

 tip. Squamulse ovate, ciliate. Stamens 2. Graiii^ 

 very large, obliquely ovoid, obtusely pointed, rather 

 longer than the palets, the cartiluginous shining per- 

 icarp not adherent to the seed. A nearly smooth 

 perennial, with running rootstocks, producing sim- 

 ple culms (2 to 3 feet high), with long, linear, lanceo- 

 late flat leaves towards the base, naked above, bear- 

 ing a few short pedicelled spikelets (1-6 to 1-4 inch 

 long) in a ^tery simple panicle. 



Name composed of dis, two, and arren man, from 

 the two stamens. 



1. D. Americana, Beauv. (Twin Grass). Shaded 

 xiver banks and woods, Ohio to Illinois, and south- 

 ward. 



28. DACTYLIS— Linseus. Orclard Grass. 



GENERIC CHARACTER. 



Spikelets several-flowered, crowded in one-sided 

 clusters, forming a branching dense panicle. Glumes 

 and lower palet herbaceous, keeled, awn-pointed, 



