112 GRAMINEAE (GKASS FAMILY) 



3-6 cm. wide, rather loosely flowered, branches somewhat contracted after 

 flowering ; spikelets 2.7-2.9 mm. long, oblong-elliptic, obtuse, villous with silky 

 hairs ; first glume 3-nerved, ^-| as long as the equal second glume and sterile 

 emma which barely cover the obtuse fruit. In late summer the stiff ascending 

 or erect culms bear numerous short crowded branches with firm sometimes nearly 

 glabrous blades, but little reduced. (P. ovale Ell. as to specimen so labeled in 

 Elliott herbarium and of description in part. The author confused a puberulent 

 narrow-leaved P. commutatum with this species, and his description is made to 

 cover both. Not P. ovale of Small's Fl.) Dry sand, N. J. to Fla. ; and about 

 L. Mich, in Mich, and Ind. 



i- 7. Columbiana. Culms rather stiff, appressiid-pubescent at least below ; 

 blades firm, thick, ascending, cartilaginous-margined, appressed-puberulent 

 on lower surface, usually glabrous on upper surface ; sheaths appressed- 

 pubescent ; ligule less than 1 mm., usually about 0.5 mm. long; spikelets 

 obovate, turgid, pubescent; the first glume \-\ as long as spikelet. Habitat, 

 sandy soil. 



50. P. Commonsianum Ashe. In large tufts ; culms ascending or spreading, 

 densely appressed-pilose, as are the sheaths ; blades flat, 6-10 cm. long, 5-6 mm. 

 wide (the upper and lower smaller), at least the lower appressed-pilose beneath ; 

 panicle 4-8 cm. long, about as broad, the branches spreading, usually with 

 few spikelets (2.5-2.7 mm. long} ; the first glume rather remote, as long as the 

 spikelet, narrow, acute ; second glume and sterile lemma equaling the fruit. 

 Branching state often purple, widely and stiffly spreading, flat on the sand, with 

 short-fascicled branches mostly from the upper nodes, and crowded stiff subin- 

 volute leaves. Dunes and sandy woods, mostly near the coast, Ct. ; s. N. J. 

 and southw. 



51. P. Addisbnii Nash. Often purplish ; culms stout, rigid, 2-4 dm. high, 

 erect or ascending, densely long-appressed-pubescent, the pubescence on the 

 sheaths shorter ; blades 5-7 cm. long, 4-6 mm. wide, glabrous above (or a 

 few hairs near the margin) ; panicle 3-5 cm. long, 2-3 cm. wide, rather 

 densely flowered, branches ascending ; spikelets 2-2.2 mm. long ; first glume 

 about half as long as the spikelet; second glume and sterile lemma barely 

 equaling the fruit. In late summer ascending or spreading, with short oppressed 

 branches from the middle and upper nodes, the reduced blades involute toward the 

 summit. Sand barrens, Ct. to N. C. 



52. P. tsugetbrum Nash. Bluish green, sometimes purplish ; culms slender, 

 2.5-5 cm. high, ascending or spreading, often geniculate below, crisp-appressed- 

 pubescent, as are the sheaths ; blades 5-6 cm. long (rarely longer), 4-7 mm. wide, 

 glabrous above or with a few long hairs near the base and margins; panicle 

 3-5 cm. long, about as wide, rather loosely flowered, branches ascending or 

 spreading; spikelets 1.9 mm. long ; first glume about $ as long as the spikelet; 

 second glume and sterile lemma equaling the fruit. More or less spreading in 

 autumnal state, freely branching from middle nodes, branches ascending ; 

 leaves not greatly reduced, scarcely involute. Sandy woods, N. Y. and N. J.; 

 also about the Great Lakes. Some forms hardly distinguishable from the next. 



53. P. columbianum Scribn. Culms rather slender, erect or ascending, 2-4 dm. 

 high, ascending-crisp-pubescent, as are the sheaths ; blades 5 cm. long or less, 

 4-5 mm. wide, mostly glabrous above; panicles finally long-exserted, 3-5 cm. 

 long, somewhat narrower, branches ascending or spreading; spikelets 1.7 mm. 

 long ; first glume $~J as long as the spikelet ; second glume and sterile lemma 

 equaling the fruit. Widely spreading but not decumbent in the autumnal state, 

 repeatedly branching from the middle nodes, the branches erect; the reduced 

 leaves involute-pointed, glabrous above. (P. psammophilum Nash.) Dry sandy 

 soil, N. E. to Ala., mostly near the coast. 



Var. thinium Hitchc. & Chase. Like small specimens of the species in the 

 simple state, but branching earlier and more profusely, decumbent, forming <li>)is<> 

 mats; the small leaves (1-2 cm. long) with scattered long hairs on the upper 

 surface; spikelets 1.3-1.4 mm. long. With the species, dry sands, N. J. 

 and Del. 



