594 GRAMINE^E. (GRASS FAMILY.) 



1' long, 8 - 10-flowered. Wet piue barrens, Florida. Culm and leaves 

 purple. 



Var. vaginatus. (A. vaginatus, Ell. Herb. !) Bracts broad, enclosing 

 the spikes. 



13. A. Mohrii, Hackel. Culms stout, 3 -4 high, the branches short 

 and rigid ; leaves and sheaths woolly; spikes 4-7, rigid, 1'- \y long, 7- 10- 

 flowered ; glumes 2" long, hispid-serrulate above, as long as the pedicel of the 

 awu-like sterile flower; awns 8" long. (A. tetrastachyus, Flora.) Around 

 pine barren ponds, West Florida and South Alabama. Sept. - Oct. 



14. A. brachystachyus, Chapm. Culms strictly erect, 4 -5 high, 

 the short and slender brandies mostly in pairs, forming a loose narrow panicle 

 2 -3 long ; leaves linear, glabrous like the sheaths ; spikes in pairs, \' long, 

 6- 8-flowered, as long as the bracts ; glumes l" long, twice the length of the 

 joints of the slender rachis, ami nearly as long as the awn ; sterile flower 

 none. East Florida ( Curtiss). 



15. A. macrourus, Michx. Culms firmly erect, 3 -5 high; leaves 

 and sheaths scabrous, and often villous ; panicle 1- 2 long, composed of ex- 

 cessively numerous crowded branches; spikes in pairs, loosely 6-8 flowered, 

 exceeding the bracts ; glumes ^ longer than the slender joints of the thinly 

 villous rachis ; sterile flower minute ; awn " long. Low ground, common. 

 Upper branches mostly bearded below the joints. 



Var. corymbosus is a reduced form of the preceding, the simple culm 

 (1 - 2 high) bearing a single corymbose 1-sided panicle. Wet pine barrens. 



Var. glaucopsis, Ell., is a more slender smooth and glaucous form, with 

 more open inflorescence, and bracts longer than the spikes. Pine barren 

 swamps. 



Var. '? viridis, Chapm. Culms 3 - 4 high, loosely paniculate with long 

 slender branches ; leaves and sheaths smooth or hairy ; bracts longer than the 

 scattered spikes. Low pine barrens near the coast, Florida. 



* * * S/n'L-es 2-5 at the summit of the culm, and 1-3 on the branches, rigid, 

 not villous, the rachis and pedicel of the triandrous awnless sterile flower 

 frint/ed with scattered hairs, and short-bearded at the base. 



16. A. f UTCatUS, Muhl. Culm stout, rigid, 3 - 5 high ; leaves rough, 

 fringed at the base ; branches commonly 2 at each upper joint ; spikelets ap- 

 pressed ; glumes hispid on the nerves, half as long as the bent awn. Open 

 woods and margins of fields. Sept. Spikes compressed, 2'-3' long. 



22. HETEROPOGON, Pers. 



Spikes solitary or digitate. Spikelets 1 -flowered, in pairs, the 2 -7 lower 

 pairs staminate or neutral, awnless, short-pedicelled, the 2 upper sessile, one 

 fertile and long-awned,the other sterile and awnless. Otherwise mainly as in 

 Andropogon. 



1. H. acuminatus, Trin. Culms 4 -8 high, branching above, the 

 uppermost branches densely corymbose ; leaves long, linear, the uppermost, 

 like the lower glume of the sterile spikelets, pitted along the midnerve; 

 spikes long-peduucled, shorter than the slender bracts ; lower spikelets tri- 



