646 GRAMINE^E. (GRASS FAMILY.) 



* Spikes erect; the rhachis JUiform and nearly terete. 



1. P. filifdrme, L. Culms very slender (l-2 high), upright; lower 

 sheaths hairy ; spikes 2-8, alternate, approximated, filiform ; spikelets oblong, 

 acute (^" long) ; lower glume almost wanting. Dry sandy soil, Massachusetts 

 to New Jersey along the coast, Illinois, and southward. Aug. 



# # Spikes spreading ; the rhachis flat and thin. 



2. P. GLABRUM, Gaudin. Culms spreading, prostrate, or sometimes erect 

 (5'- 12' long), glabrous; spikes 2-6, widely diverging, nearly digitate; spikelets 

 ovoid (about I" long) ; upper glume equalling the flower, the lower one almost want- 

 ing. Cultivated grounds and waste places : common, especially southward : in 

 some places appearing as if indigenous. Aug., Sept. (Nat. from Eu.) 



3. P. SANGUINALE, L. ( COMMON CRAB- Or FlNGER-GRASS.) Culms erect 



or spreading (1 - 2 high) ; leaves and sheaths glabrous or hairy ; spikes 4-15, 

 spreading, digitate; spikelets oblong (l" long) ; upper glume half the length of the 

 flower, the lower one small. Cultivated and waste grounds. Aug. - Oct. (Nat. 

 from-Eu.) 



2. PANICUM proper. Spikelets scattered, in panicles, awnless. 



* Panicle elongated and racemose, wand-like or pyramidal ; the numerous and usually 



pointed spikelets short-pedicelied, excepting 2Vb. 7 and 8. 



- Sterile flower neutral and of 2 palets, fully twice the length of the lower glume: 

 spikelets small (1" or 1^" long) : root perennial. 



4. P. anceps, Michx. Culms flat, upright (2 -4 high); leaves rather 

 broadly linear (l-2 long, 4"-5" wide), smooth; panicle contracted-pyramidal ; 

 spikelets ovate-lanceolate, pointed, a little curved ; upper glume 5 - 7 '-nerved; neutral 

 flower one third longer than the perfect one. Wet sandy soil, New Jersey and 

 Penn. to Virginia, and southward. Aug. Too near the next : spikelets and 

 branches of the panicle longer. 



5. P. agTOStoideS, Spreng. Culms flattened, upright (2 high) ; leaves 

 long, and with the sheaths smooth ; panicles terminal and often lateral, pyram- 

 idal (4' -8' long) ; the spikelets racemose, crowded and one-sided on the spread- 

 ing branches, ovate-oblong, acute (purplish) ; upper glume 5-nerved, longer than the 

 neutral flower which exceeds the perfect one ; perfect flower bearded at the apex. 

 (P. agrostidiforme, Lam. ? P. multiflorum, Poir.) Wet meadows and shores, 

 E. Massachusetts and New York (Oneida Lake, A. H. Curtiss) to Illinois, and 

 common southward. Aug. 



H- *- Sterile flower neutral and of a single palet, much longer than the lower glume; 



spikelets %" -l" long ; annuals except No. 8 : leaves flat; sheaths flattened. 

 ++ Glabrous and smooth throughout ; spikelets crowded, oppressed, short-pedicelled. 



6. P. proliferum, Lam. Culms usually thickish and rather succulent, 

 branched, geniculate and ascending from a procumbent base ; sheaths flattened ; 

 ligule ciliate ; panicles terminal and lateral, compound, pyramidal, the slender 

 primary branches at length spreading; spikelets pale green, rarely purplish; 

 lower glume broad, J to i the length of the upper ; neutral flower little longer 

 than the perfect one. Marshy river-banks and shores, especially when brack- 

 ish, but also in the interior, from Mass, and Illinois southward. Aug. 



