GRAMINE^E. (GKASS FAMILY.) 593 



* * Spikes 2, and in pairs, rarely 4, or more, hoary with long spreading hairs, 

 the peduncle sheathed by a leaf-like bract: sterile flower a single glume, or 

 obsolete. 



t- Bract mostly shorter than the peduncle, its blade very short or none (in No. 1 



variable). 



7. A. Elliottii, Chapm. Culms 2 - 3 high, bearded at the upper joints, 

 the branches short ami simple; leaves narrow-linear, the lower sheaths hairy, 

 the upper smooth and mostly densely crowded and enlarged ; spikes 2 (rarely 

 4), long-exserted, or included in the upper sheaths, loosely 8 - 10-flowered, 

 tin- hairs long and glossy ; glumes scabrous, 1\" long, one third as long as the 

 straight awn. Dry pine barrens. Sept. 



8. A. arctatus, Chapm. Culm single (2 -5 high), the appressed 

 branches narrowly paniculate ; leaves and sheaths shaggy with long white, 

 mostly deciduous hairs; spikes by pairs (I'-l^'loug), rather stout, closely 

 1 5 20-fiowered ; glumes rough, twice as long as the joints of the rachis; 

 hairs of the rachis few and short; stamen 1. Low pine barrens, Florida. 

 Sept. - Oct. 



9. A. argyraeus, Schultes. Glabrous and more or less glaucous ; culms 

 2 high ; branches simple, erect, the lower single, the upper in pairs, bearded 

 below the upper joints; leaves linear, 6 - 8 long ; spikes 2, 1J'- 2' long, 10- 12- 

 flowered, densely villous, the stout peduncle closely enwrapped by the leafless 

 bract ; glumes 2-J" long, smooth, nerveless, longer than the rigid very villous 

 joints of the rachis ; awns 1' long ; stamens 3. Dry soil in the lower districts. 

 Sept. - Oct. 



10. A. Cabanisii, Hackel. Habit and most of the characters of the pre- 

 ceding, but the spikes narrower and 10- 15-flowered, the rachis less villous, 

 with shorter hairs ; lower glume scabrous, and faintly nerved ; awns \' long. 

 South Florida (Garber). 



-t- -i- Bract longer than the peduncle (except No. 15), its blade mostly longer than 



ihe spikes. 



11. A. longiberbis, Hackel. Culms 2 high, loosely paniculate above 

 the middle ; leaves linear, smooth, 5' -10' long, the lower sheaths appressed- 

 pubescent ; spikes 2, rather rigid, closely 10 12-flowered, shorter than the 

 bracts, the straight rachis densely villous with long spreading hairs ; glumes 

 2" long; pedicel tipped with a subulate glume. South Florida (Garber, 

 Simpson). 



12. A. Virginicus, L. (BROOM GRASS.) Culms 3 -4 high, narrowly 

 paniculate above the middle ; leaves linear, mostly glabrous, like the sheaths ; 

 spikes 2-4, 9" 12" long, loosely 6 -10-flowered, the very slender flexuous 

 rachis rather sparselv villous; glumes 1^" long, one third longer than the 

 joints, these naked below; sterile glume none; awns 6" -8" long. In open 

 ground, everywhere. Sept - Oct. The most marked varieties are : 



Var. tetrastachyus, Hackel. Culms stouter ; leaves and sheaths villous 

 with spreading hairs; spikes 4, 1'- lj' long, 12-16-flowered. Low ground, 

 Florida and Alabama. 



Var. stenophyllus, Hackel. Culms slender, strictly erect ; branches 

 straight and erect or appressed ; leaves narrow-linear or filiform, erect ; spikes 



38 



