384 



ORDER loo. GRAMINE^E. 



5. AGROSTIS, L. BENT GRASS. Spikelete 

 1-flwd. Glumes 2, subequal, awnless, usually 

 longer than the flower. Pales 2, thin, pointless, 

 naked, the lower 3-5-veined, sometimes awn eel 

 on the back, the upper often minute or wanting. 

 Grain free. Mostly y, caespitous, with slender 

 culms and open panicles. 



AoR6sTis. Upper pale conspicuous. Panic.'o 



rather dense Nos. 1, 2 



TRICHOIHUM. Upper pale minute or wanting. 



Panicle thin, capillary. . . (*) a 



* Lower palea with a long exserted awn on the back Nog. 3, 4 



* Lower palea awnless, or bearing a very short awn Nos. 5, 6 



1 A. vulgaris Wilh. Red-top (a). Culm erect, 1 2f; pan. purple, oblong, with 



short branches ; ligules very short ; lower pale (b) 3-veined, twice longer than the 

 upper, nearly awnless. A valuable grass : common. 



% A. alba. L. Florin G. Culm decumbent and rooting at the lower joints, then as 

 cending 1 3f, stoloniferous ; ligules long (3 4") : pan. greenish-white, or purplish, 

 contracted ; pale 5-veined, awned or not. Common. 



3 A. caiiina L. Dog's or Brown B. Decumbent and rooting at base, 1 2f; leaves 



setaceous-rolled ; pan. brownish ; lower pale and awn exserted. Wet meadows. E. 

 ft. alpina. Culms low, in tufts, with wide panicles, and twisted awns. Mts. 



4 A. aracliuoides Ell. Erect, 58', pan. fits length; Ivs. linear-setaceous; lower 



pale, i", its awn as fine as a gossamer, twisted, 34" long. S. C., Ga., and W. Apr. 



5 A. .sco. bra Willd. Rough Hair O. Erect from a decumbent base, 1 2f, very slen- 



der, all scabrous-hispid ; pan. large, capillary, spkl. purplish, (c, glumes, tf, flower). 

 The thin, airy panicles are at length driven before the wind. Fields and pastures. 

 June Aug. 



/3. pertnnan*. Panicle pale-green, the branches shorter. In damp shades. 



y. oreophtla. Pan. less diffuse ; lower pale with a short twisted awn. Mts. 



6 A. olata Trin. Culms stoutish, simple, erect, 2 3f ; Ivs. broadly linear; pan. pur 



pie, with long suberect whorled branches dense-flowered half their length ; gls. W 

 long, lower pale 5-veined, 1". Swamps, N. J. to Ky., and S. Sept., Oct. 



6. SFOROBOLUS, Br. DROP-SEED GRASS. Spikelets 

 1-flwd. Gls. 2, the lower smaller. Fls. sessile. Pales 2, 

 awnless, usually longer than the glumes. Sta. 2 or 3. Grain 

 deciduous, free, if Tough, wiry, with rolled rigid leaves 

 and contracted panicles often half-enclosed in the sheath. 



$ VILFA. Grain (caryopsis) linear. Glumes and pales all 



sub-equal. Panicle contracted Nos 13 



| SPOROBOLUS. Grain oval or globous, its pericarp often 



loose on the seed ... (a) a 



a Glumes very unequal, one of them as long as the purplish pales Nos. 46 



a Glumes equal or unequal, both shorter than the pales. Sheaths beardless.. .(b) 

 b Panicle contracted, spikeform, sheathed or exserted. Lvs. involute. . .Nos. 7, 8 

 b Panicle capillary, open. Often a 2d flower or rudiment. Lvs. flat. . .Nos. 9, 10 

 1 S. vaginaeflorus Torr. (a.) Culms in tufts, simple, ascending, 612' ; Ivs $-4' ; 

 panicles lateral and terminal, mostly concealed in the tumid sheath* ; grain } suort-.*r 

 than the 2" pales. CD Dry gravel. More common W. and S. 



