GUAMINEAE (GRASS FAMILY) 113 



+- 8. Ensifblia. Delicate,^ densely tufted, mostly glabrous; spikelets not over 

 1.5 mm. long ; ligule obsolete. 



54. P. ensif61ium Baldw. Culms 2-3.5 dm. high, glabrous, ascending or 

 spreading, from dense tufts of ascending basal leaves ; these 3-7 cm. long, 4-5 mm. 

 wide, remaining green throughout the summer ; sheaths glabrous, much shorter 

 than the long iriternodes ; culm-blades 0.7-2 cm. long, 1-2 mm. wide, spreading, 

 usually puberulent beneath; panicle 1.5-3 cm. long, nearly as wide, rather few- 

 flowered ; spikelets 1.5 mm. long, obovate-elliptic, turgid at maturity, densely 

 puberulent; second glume slightly shorter than the obtuse fruit. Branching 

 from the upper nodes in the autumnal state, culms usually decumbent, branches 

 short, not very -numerous. (P. Brittoni Nash.) Borders of cranberry bogs, 

 s. N. J., and low pine lands south w. 



P. TEXUE Muhl. (P. unciphyllum Trin. ; P. albo-marginatum Nash) has been 

 collected in the Great Dismal Swamp, Va. (Chase). This is characterized by 

 the larger and firmer leaves clustered at the base of the culms and having, 

 especially when dry, conspicuous cartilaginous white margins. 



t- 9. Sphaerocdrpa. Rather stout, glabrous; blades firm, cordate at base, 

 scabrous on upper surface, margins cartilaginous; ligule nearly obsolete; 

 spikelets obovoid-sphericai, puberulent ; second glume and sterile lemma 

 1-nerved, equaling fruit at maturity. Sparingly branched or nearly simple 

 in autumn. 



55. P. sphaerocdrpon Ell. Dull green ; culms 2-5.5 dm. high, usually widely 

 spreading, nodes appressed-pubescent ; sheaths nearly as long as the internodes 

 or overlapping, loose toward the summit, ciliate on the margin ; 



blades 6-10 cm. long, 7-14 mm. wide (uppermost smaller,, thick, >^PV 



ascending, stiff-ciliate toward the base, nerves inconspicuous; jjjjj 



panicle long-exserted, 5-10 cm. long, nearly as wide, rather w 



loosely flowered, with viscid spots on the axis and ascending 

 branches ; spikelets usually purple, 1.6-1.8 mm. long ; fruit china- 65. P. sphaero- 

 white. Sparingly branching from the lower nodes late in the carpon. Spike- 

 season ; leaves and panicles not much reduced. Sandy ground, let x 5. 

 Mass, to Kan., and southw. FIG. 65. 



56. P. polydnthes Schultes. Light green, erect; culms 3-9 dm. high, nodes 

 glabrous; sheaths very long, usually overlapping, margin finely ciliate ; blades 

 12-23 cm. long, 1.5-2.5 cm. wide (uppermost not smaller), strongly nerved, 

 ciliate toward the base ; panicle 8-25 cm. long, not more than half as wide, 

 densely flowered, lower branches nearly erect, often distant; spikelets green, 

 1.5-1.6 mm. long; fruit stramineous. Culms simple or very sparingly 

 branched from the lower or middle nodes late in the season. (P. micro- 

 carpon Muhl. Gram., not Ell.) Damp ground, woods and openings, N. Y. 

 to I. T., and southw. 



- 10. Commutata. Stout, erect, glabrous or puberulent only ; leaves cordate, 

 over 1 cm. wide (sometimes less in P. Ashei} ; ligule nearly obsolete ; panicles 

 open, loosely flowered ; spikelets oblong or elliptic, not turgid, pubescent, 

 2.6-3 mm. long; second glume and sterile lemma strongly 1-nerved. 



57. P. commutatum Schultes. In large or small clumps ; culms 4-7. 5 dm. high, 

 usually stiff, erect and glabrous, nodes puberulent ; sheaths glabrous or puberu- 

 lent toward the summit, a pubescent ring at the junction with the blade, margin 

 ciliate; blades rather firm, spreading or ascending, 5-12 cm. long, 1.2-2 cm. 

 wide (rarely longer or wider), glabrous on both surfaces (rarely puberulent), 

 margins ciliate toward the base ; panicle 6-11 cm. long, as wide or wider; spike- 

 lets 2.6-2.8 mm. long, oblong-elliptic, obtuse ; second glume and sterile lemma 

 equal, barely covering the minutely umbonate fruit. In autumnal state culms 

 ascending or spreading, with somewhat divaricate simple branches from the 

 middle nodes; the leaves crowded but hardly reduced. (P. subsimplex Ashe.) 

 Woods and copses, Del. to Fla., w. to 111. and Tex. 



58. P. Ashei Pearson. Usually purplish, in loose clumps from a knotted 

 crown ; culms 2.5-5 dm. high, erect, stiff, wiry, densely crisp-puberulent ; sheaths 



GRAY'S MANUAL 8 



