GUAMiNi:^. (grass fa^iily.) 581 



flower fringed with closely appresscd white hairs ; spikelets awnlcss ; glumes 

 hispid above ; sterile flower of 2 palerr, 3-androus. (Rottba-llia ciliata, Niilt.) — 

 Low pine barrens, Florida and the lower districts of Georgia. Sept. — Spikes 

 3' - 6' long. 



2. A. oligOStachyus. Culms rigid, erect ; leaves linear, smooth, glaa- 

 cous ; spikes 3-4, on short mostly included peduncles, hoary with short spread- 

 ing hairs ; lower glume pubescent, i- J as long as the contorted awn; sterile 

 flower neutral, sliort-awned. — Dry sand-ridgcs, Middle Florida. Aug. and 

 Sept — Culm 2° - 3° high. Spikes 2' - 3' long. 



3. A. tener, Kunth. Culms filiform, like the smootii soon involute leaves ; 

 spikes terete, witli the joints bearded at the base, otherwise smooth ; spikelets ap- 

 presscd, half as long as the bent awn ; glumes rough above ; upper palea minute ; 

 pedicel of the awnless neutral flower bearded at the apex. — Dry grassy pine 

 barrens, Georgia, Florida, and northward. Sept. — Culms 2° -3° long. Spikes 

 slender, 1'- 2' long. Upper leaves short, bearded at the throat. 



* * Peduncles clustered, each bearing a single spike. 



4. A. SCOparius, Michx. Leaves smooth or rough-hairy ; spikes numer- 

 ous, on exscrted peduncles, the slender flexuous raehis, and pedicel of the awned 

 or awnless staminate or neutral sterile flower fringed with spreading hairs ; per- 

 fect flower half as long as the awn, the glumes often roughened with elevated 

 points. — Dry sterile soil, Florida, and northward. Aug. and Sept. — Culms 

 20 - 3° high. Spikes 1 ' - 2' long. 



♦ * * Peduncles or branches inosdg clustered, hearing 2-4 rigid {green) digitate 



spikes : raehis and pedicel of the triandrous awnless sterile fiower fringed with 

 scattered hairs, and short-bearded at the base. 



5. A. furcatus, Mulil. Culm stout, rigid, 3° - 5° high ; leaves rough, 

 fringed at tiie base ; peduncles or branches commonly several at each upper 

 joint ; spikelets appresscd ; glumes hispid on the nerves, half as long as the bent 

 awn. — Open woods and margins of fields, Florida, and northward. Sept. — 

 Spikes compressed, 2' -3' long. 



♦ * * * Peduncles or branches 1 - several from each upper joint, often included in the 



dilated sheaths: spikelets slender, hoary with long silkij spreading hiiirs: sterile 

 flower reduced to an awn-like glume at the apex of the very slender pedicel, or 

 obsolete: stamen 1. 



6. A. tetrastachyus, Ell. Culms 3° - 4° high ; leaves and sheaths very 

 hairy ; branches short, the lower ones by pairs, the upper single ; spikes 4 ; 

 glumes bristly-serrulate, one fourth as long as the straight awn ; pedicel of the 

 awn-like sterile flower barely exceeding the fertile flower. — Var. i)iST.\cnvu8. 

 Leaves and sheaths less hairy or smoothish ; spikes by pairs, more rigid, on 

 long-exscrted branclv^s ; pedicel of tlie sterile flower much longer than the 

 smoother glumes. — Low pine barrens, Florida to North Carolina. Sept. 



7. A. Elliottii. Culms 10-2° high, bearded at the upper joints; leaves 

 purplish, nnrrow, hairy at the base; sh atlis hairy, the upper ones inflated and 

 often crowded or imbricated : branches single or l)y pairs; spikes by pairs (rarely 



49* 



