646 GRAMINEJE. (GRASS FAMILY.) 



* Spikes erect ; its rhachis filiform and nearly terete. 



1. P. filiforme, 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 ; its rhachis flat and thin. 



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

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

 ovoid (about 1" 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 Finger-Grass.) Culms erect 

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

 spreading, digitate; spikelets oblong (1|" long) ; upper glume half the length oftlie 

 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-pedicelled, excepting No. 7 and 8. 



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

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



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

 broadly linear ( 1 ° - 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. agrostoides, 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. 



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



spikelets £" -lj" 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 ; 

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

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

 lower glume broad, J to \ 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. 



