630 GRAMlNEiE. (GRASS FAMILY.) 



§ 1. DIGITARIA. Spikelets crowded 2-3 together in simple and mostly 1 

 sided clustered spikes or spike-like racemes, wliolly awnless and pointless^ 

 \-Jlowered ; lower glume minute or obsolete or wanting ; annual, q/len purplish. 

 * Spikes erect ; the rhachis Jiliform and nearly terete. 



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

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

 acute {^" long); lower glume almost wanting. — Dry sandy soil, Mass. to 

 N. J. along the coast, to Iowa, Neb., and southward. Aug. 



* * Spikes spreading ; the rhachis flat and thin. 



P. glXbrum, Gaudin. Culms spreading, prostrate, or sometimes erect 

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

 lets ovoid (about V long) ; upper empty glume equalling the flower, the lower 

 almost wanting. — Cultivated grounds and waste places; common, especially 

 southward; sometimes appearing indigenous. Aug., Sept. (Nat. from Eu.) 



P. SANGuixlLE, L. (Common Crab- or Fixger-Gkass.) (PI. 13, fig. 

 1-3.) Culms erect or spreading (1-2° high); leaves and sheaths glabrous 

 or hairy; spikes A- \b, spreading, digitate; spikelets oblong (l^"long); sec- 

 ond 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-pedicelled ^ excepting n. 3 and 4. 



H- Sterile flower none; lower glume short; spikelets ^-\^" long ; annuals except 



n. 4; leaves flat; sheaths flattened. 



•*-*■ Glabrous and smooth throughout ; spikelets appressed, short- pedicelled. 



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

 branched, geniculate and ascending from a procumbent base ; sheaths flat- 

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

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

 purplish ; lower glume broad, g to | the length of the upj)er, which is little 

 longer than the flowering one. — Marshy river-banks and shores, especially if 

 brackish, but also iu the interior, from Mass. to Iowa, and southward. Aug. 

 *+ ++ Hispid or hairy on the sheaths, at least the lower ; spikelets mostly scattered 



on slender pedicels in an ample, loose, at length very efl^use panicle ; culms 

 mostly bra'uched from the base, erect or ascending (10-20' high). 



3. P. capillare, L. (Old-witch Grass.) (PI. 13, fig. 4, 5.) All the 

 sheaths and usually the leaves copiously hairy or hispid ; panicle mostly very 

 compound, the branches divaricate when old ; spikelets from ovoid to narrowly 

 •oblong, pointed; lower glume half the length of the upper empty one, which is 

 longer than the elliptical obtuse perfect flower. — Sandy soil and cultivated 

 fields everywhere. Aug. - Oct. — Varies extremely in size and appearance, 

 the culms erect and simple, or decumbent, geniculate and branched ; in de- 

 pauperate forms the spikelets only f", in the larger forms H" in length. 



4. P. autumnale, Bosc. Root perennial (? ), lower sheaths and margins 

 of the small narrow leaves more or less hairy, otherwise glabrous, except some 

 bristly hairs in the main axils of the very effuse capillary panicle, its much 

 elongated divisions sparingly branched, or even simple and terminated with 

 solitary sju//it//e-shaped spikelets; lower glume minute ; perfect flower lanceolate- 



