582 GRAMINE^. (grass FAMILY.; 



3-4), exsertcd, or included in the upper sheaths ; awn 3-4 times the length of 

 the glumes ; hairs of the veiy slender rachis long and glossy. (A. argenteus, 

 EU., not of DC.) — Wet or dry pine barrens, Florida to North Carolina. Sept. 

 and Oct. — Somewhat variable, but distinguished by the dilated clustered sheaths, 

 and by the silvery hairs of the spikes. 



8. A. Virginicus, L. Culms mostly tall, erect or bending, with the joints 

 remote and bearded ; branches 1-2 from the upper dilated sheaths, compound 

 and forming a long and loose panicle; spikes hy pairs (rarely by fours), shorter 

 than the sheaths ; awn straight, four times the length of the glumes ; sterile flower 

 none. (A. vaginatus, Ell., the short branches or peduncles included in the more 

 inflated sheaths. A. dissitiflorus, Michx. 1 A. gracilis, Carpenter, the spikes 

 borne at the summit of elongated simple branches. _) — Barren soil, Florida to 

 Mississippi, and northward. Sept. and Oct. 



9. A. macrourus, Michx. Spikes by pairs, exceedingly numerous, crowd- 

 ed in a large and close panicle ; awns 3-4 times the length of the glumes ; sterile 

 flower an awn-like glume. — Varies with the whole plant glaucous and more 

 slender, branches and spikes more scattered. — Low barren soils, Florida, and 

 northward. Se])t. — Culms 2° - .5° high. 



10. A. ternarius, Michx. " Branches remote, alternate, sohtary, simple, 

 bearing mostly three distant alternate 2-cleft spikes ; hairs of the involucre shorter 

 than the glume; flowers 3-androus; palcoe somewhat villous; awn long, con- 

 torted." Michx. In Carolina. ( * ) 



§ 2. HETEUOPOGON. — Upper Jlower staminate or pistillate. 



11. A. melanocarpus, Ell. Culms tall (4°-8° high) panicled above; 

 leaves elongated ; spikes numerous, appro.ximate, 1 -sided, shorter than their 

 slender filiform-pointed sheaths ; spikelets lai-ge, the two lowest pairs glume-like, 

 persistent, sterile, the others deciduous ; sterile flower 3-androus, with the lower 

 glume lanceolate, membranaceous, twisted, much longer than the fertile spikelct 

 and the smooth and short pedicel ; fertile spikelct rusty bearded ; the coriaceous 

 glumes obtuse, many times shorter than the very long (4') contorted and hairy 

 awn. — Indian old fields, Florida and Georgia. Introduced? — Glume of the 

 sterile spikelct, like the sheaths, rugose on the back. Perhaps identical with 

 A. polystachyus, Roxb. 



57. ERIANTHUS, Michx. 



Tall reed-like grasses, with long and flat leaves, and panicled inflorescence. 

 Spikelets by pairs on the slender branches, alike, one pedicelled, the other ses- 

 sile, both with a hairy involucre at the base. Lower flower of one palea, neutral ; 

 the upper of two paleae, perfect, shorter than the membranaceous .nearly equal 

 glumes, the lower one awned. Stamens 2-3. 



1. E. alopecuroides, Ell Culms 4°-10° high; sheaths of the broad 

 (6"- 12") very rough leaves woolly above, rough below ; panicle (1° - 2° long) 

 woolly, expanding, pyramidal; hairs of the involucre copious, twice as long as 

 the sparsely hair}- glumes ; awn straight. — Var. contortus. (E. contortus. Ell.) 



