GRAMINE.E. (GRASS FAMILY.) 581 



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

 above ; leaves lauceolate, rather thin, 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 piue 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 branches erect (l-3 high), branching; leaves linear-lanceolate, 

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

 panicled 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 panicled. 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 perfect, coriaceous, 

 awuless, enclosing the free grain. Stamens 3. 



1. DIG IT ARIA. Inflorescence spiked, digitate: spikelets 2-3 together, im- 

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

 shorter than the floret : mostly annuals. 



1. P. sanguinale, L. (CRAB-GRASS.) Culms ascending from a dif- 

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

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

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

 waste places everywhere. May -Oct. 



2. P. filiforme, L. Culms erect, sparingly 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 l'-2' long; spikes 2 - 4, digitate, l'-2' long; spike- 

 lets ovoid. Cultivated ground. Introduced. 



4. P. serotinum, Michx. Perennial, creeping, much branched ; leaves 

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

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



2. PANICUM proper. Glumes awnless, 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-J-2 high; leaves 

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

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

 nearly half as long as the spikelet. (P. tenuiculmum, Flora.) South 

 Florida. 



