108 GRAMIKEAE (GRASS FAMILY) 



sterile 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 Jlat leaves 2-4 cm. long. 

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



31. P. microcarpon Muhl. Culms 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 leaves shorter and broader ; panicles long-exserted, 10-12 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. polyanthes Schultes ; P. barbulatum 

 Am. auth., riot Michx. ) Wet woods and swampy places, Mass, to 111., s. to 

 Fla. and Tex. Spikelets rarely sparsely pubescent. 



M. -M. 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 margin, 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 } 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 N. 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. Clutei Nash.) Sandy 

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



34. P. annulum Ashe. Purplish ; culms 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., Pa., and D. C. to Ga. ; apparently rare. 



i-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 in the autumnal state, the tufted branches shorter than the 

 elongated primary internodes; the reduced crow'ded leaves often conduplicate, 



