108 GRAMINEAE (GRASS FAMILY;^ 



Hterile lemma both shorter than the fruit. In late summer the delicate culms are 

 almost creeping and vine-like, repeatedly branching, the branches elongated and 

 diverging at a wide angle, not fascicled; the waxy flat leaves 2-4 cm. long.~ 

 Wet woods and sphagnum swamps, N. J., D. C, and southw. 



31. P. mlcrociirpon Muhl. Cuhns at first erect, in large clumps; nodes 

 swollen, densely bearded with reflexed hairs ; sheaths less than half as long as the 

 internodes, ciliate on the margin, the lower sometimes pilose ; blades 10-12 cm. 

 long, 10-12 mm. wide, thin, spreading or deflexed, ciliate at base, otherwise 

 glabrous ; basal lea,ves shorter and broader ; panicles long-exserted, i0-12 cm. 

 long, branches ascending, with numerous spikelets 1.6 mm. long ; second glume 

 slightly longer than the fruit. Becoming diffusely branched, reclining or pros- 

 trate, with densely crowded small flat leaves and numerous very small panicles. 

 (Muhl. in Ell., not Muhl. Gram., which is P. pohjanthes Schnlles ; P. barhulatum 

 Am. auth., not Michx.) — Wet woods and swampy places, Mass. to 111., s. to 

 Fla. and Tex. — Spikelets rarely sparsely pubescent. 



++ ++ Spikelets pubescent. 



32. P. boreale Nash. Culms 3-5 dm. high, slender, erect, or in weak forms 

 geniculate at base ; nodes sometimes with a few hairs ; sheaths often overlapping, 

 ciliate on the margm, glabrous, or the lower sparsely pubescent ; blades 6-12 

 cm. long, 7-12 mm. wide, erect, sparingly ciliate toward the rounded base, other- 

 wise glabrous (rarely puberulent beneath) ; panicle 5-10 cm. long, hardly as 

 wide, loosely flowered, the slender branches ascending or spreading ; spikelets 

 2.2 mm. long, obtuse ; first glume A as long as the subequal second glume and 

 sterile lemma, which are as long as the fruit. Sparingly branched from all the 

 nodes in late summer; leaves and panicles not greatly reduced. — Moist open 

 ground or woods, Nfd. to Ont., s. to JM. E., N. Y., n. Ind., and Minn. 



33. P. mattamuskeetense Ashe. Often purplish ; culms 0.4-1 m. high, erect 

 or geniculate at base, glabrous ; nodes puberulent ; sheaths loose, short, upper 

 glabrous except on the margin and sometimes the summit, lower usually softly 

 pilose ; blades 6-9 cm. long, 6-12 mm. wide (upper and lower smaller), spread- 

 ing, often reflexed, glabrous ; panicle 6-10 cm. long, the flexuous branches 

 spreading, spikelet-bearing almost to the base; spikelets 2.3 mm. long ; second 

 glume and sterile lemma subequal, both shorter than the subacute fruit. 

 Remaining erect, branching from the middle nodes in late summer, the branches 

 rather appressed ; rameal leaves stiffly ascending. (P. Glutei Nash.) — Sandy 

 borders of cranberry bogs and swamps, Mass., N. J., and southw. 



34. P. dnnulum Ashe. Purplish ; cuhns erect, 5-7 dm. high, in small clumps ; 

 nodes densely bearded ; sheaths glabrous or the lower softly pubescent ; blades 

 6-12 cm. long, 7-13 mm. wide, spreading, velvety-pubescent on both surfaces, 

 margins ciliate toward the base ; panicles 5-9 dm. long, open ; spikelets 2 mm. 

 long ; second glume slightly shorter than the fruit. Erect and sparingly branched 

 from the upper nodes in late summer, soon dying to the ground. — Dry woods, 

 N. J., Fa., and D. C. to Ga. ; apparently rare. 



•♦-5. Spreta. — Plants mostly glabrous or at least not spreading-pilose ; blades 

 firm; ligule dense, 2-5 mm. long; spikelets densely pubescent, 1.6 mm. 

 long or less. 



35. P. sprdtum Schultes. Culms erect or slightly decumbent at base, glabrous ; 

 nodes swollen, usually naked ; sheaths loose, shorter than the internodes, usually 



ciliate on the margin above, otherwise glabrous, or the lower 



sparsely pubescent; ligule 2-3 mm. long ; blades 7-10 cm. long, 



4-8 mm. wide, ascending, often reflexed, sparingly long-ciliate 



at base, otherwise glabrous ; panicle 8-12 cm. long, less than 



half as wide, rather dense, the fascicled branches ascending or 



64. P. spretum, appressed, short spikelet-bearing branches at the base of the 



Spikelets x 5. fascicles; spikelets 1.5-1.6 mm. long, elliptic, obscurely pointed; 



second glume and sterile lemma equal, slightly exceeding the fruit. 



Somewhat reclining \\\ the autumnal state, the tufted branches shorter than the 



elonaated vriT.\a^'y internodes ; the reduced crowded leaves often conduplicate, 



