646 GKAMiNE^. (grass family.) 



* Spikes erect; its rhachis filiform and nearly terete. 



1. P. fllif6rine, L. Culms very slender (l°-2° high), upright; lower 

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

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

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



* * Spikes spreading; its rhachis fiat and thin. 



2. P. GLinEnM, 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 thefiower, 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. aANGumALE, L. (Common Crab- or Fingeb-Gkass.) Culms erect 

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

 spreading, digitate; spikelets oblong (1^" long) ; upperglume half the length of the 

 fiower, 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. 



•*- Sterile fiower neutral and of ^ palets, fully twice the length of the lower glume: 



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



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

 broadly linear (l°-21ong, 4" -5" wide), smooth; panicle contracted-pyramidal ; 

 spikelets ovate-lanceolate, pointed, a little curved ; upper glume 5 - 1 -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. agrostoldes, Spreng. Culms fiattened, 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 %vhich exceeds the perfect one ; perfect flower bearded at the apex. 

 (P. agrostidiforme, Lam. ? P. raultiflorum. Pair.) — Wet meadows and shores, 

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

 common southward. Aug. 



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

 spikelets ^"-Ij" long ; annuals except No. 8 : leaves fiat ; sheaths fiattened. 

 ** Glabrous and smooth throughout ; spikelets crowded, appressed, 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 J 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. 



