GRAMINE^. (grass FAMILY.) 581 



1. A. Purshii, Kunth. Culms tufted, erect from fibrous roots, naked 

 above ; leaves lanceolate, rather thiu, clothed, like the sheaths, with spreading 

 rigid hairs ; upper flowers in a strict panicle ; those at base of the culm 

 perfect ; grain ovoid or oblong, terete. — Low sandy pine barrens, Georgia, 

 and northward. Sept. — Culms 1°- 3° high. Glumes of the upper flowers 

 5 nerved, of the lower one white, many-nerved. 



2. A. Floridanum, Chapm. Culms subterraneous, diffusely creeping; 

 flowering brandies erect (l°-3'^ h'g'i); branching; leaves linear-lanceolate, 

 rigid, smooth ; sheaths fringed on the margins ; upper spikelets abortive, 

 pauicled or racemed, oblong (3" long), acute ; glumes 5-nerved; grain com- 

 pressed-globose, pointed. — Sandy pine barrens, Florida. Sept. - Oct. 



7. PANICUM, L. Panic Grass. 



Inflorescence spiked, racemose, or pauicled. Spikelets 2-flowered, naked 

 (no involucre). Empty glumes 2 or 3, herbaceous ; the lowest smaller, often 

 minute, or occasionally wanting. Lower flower staminate or neutral ; the 

 palet, when present, small and hyaline. Upper flower i)erfect, coriaceous, 

 awnless, enclosing the free grain. Stamens 3. 



§ I. DiGiTAKiA. — Inflorescence spiked, digitate: spikelets 2-3 together, im- 

 bricated on one side of the slender rachis : lower Jlower neutral: glumes 

 shorter than the floret : mostly annuals. 



\. P. sanguinale, L. (Crab-Grass.) Culms ascending from a dif- 

 fusely creeping base ; leaves thin, spreading, the lower part, like the sheaths, 

 hairy; spikes 5 "-10, digitate and alternate, 3' -5' long, spreading; spikelets 

 oblong, pointed ; glumes hairy on the margins. — Cultivated grounds and 

 waste ])laces everywhere. May - Oct. 



2. P. filiforme, L. Culms erect, spanngly branched (2°-3° high); 

 leaves linear, erect, and, like the sheaths, hairy ; spikes 2-5, alternate, erect, 

 filiform, 2'- 10' long; spikelets oblong, acute, scattered. — Dry sandy soil, 

 common. August - Sept. 



3. P. glabrum, Gaudin. Glabrous or nearly so ; culms branching be- 

 low, 6' - 12' high ; leaves 1' - 2' long ; spikes 2 - 4, digitate, 1'- 2' long ; spike- 

 lets ovoid. — Cultivated ground. Introduced. 



4. P. serotinum, Michx. Perennial, creeping, much In-anched ; leaves 

 short (1' long), lanceolate, villous, like the sheaths; spikes mostly .5, digitate; 

 spikelets minute. — Fields and roadsides, Florida to North Carolina. 



§ 2. Panicum proper. — Glumes aimless, the 2 lower very unequal, empty ; 



spikelets panicled or racemed. 

 * Panicle simple, composed of short l-sided spike-like branches racemose at the 

 summit of the culm; spikelets mostly longer than their pedicels. 

 •5. P. Chapmanii, Vasey. Culms slender, erect, l|°-2° high; leaves 

 narrow-linear ; branches 4-12, remote, 3 - 6-flowered, V long ; rachis flexuous, 

 bristle-like at the apex; spikelets oblong, 1" long; lowest glume roundish, 

 nearly half as loug as the spikelet. (P. tenuiculmum. Flora.) - South 

 Florida. 



