664 POACE^. 



on the keels. Nearly allied to P. Jlexuosa, but its first glume is 3- 

 nerved, the floral glume longer and strongly pubescent. 

 Illinois, U. S. Dept. Agricul. 360 from J. Wolfe. 



39. P. laxa Haenk. Sudet. 118 (1791). P. flextioaa J. E. Smith,. 

 Fl. Brit. 1:101 (1800), not Wahl. (1824), not Muhl. (1817). 



Tufted, smootli, flaccid throughout, slender, ascending or erect 

 from a geniculate base, 10-25 (rarely 35) cm. high. Ligule 2-2.5 

 mm. long; blades flat, acuminate, 4-6 cm. long, 1.5-2 mm. wide, 

 those of the culm 2-3 in number. Panicle 5-10 cm. long, simple, 

 linear, dense and interrupted or spreading and nodding, rays 

 flexuose, 1-5 (mostly 2-3) at a node of panicle. Spikelets often 

 pu' r'.ii, sometimes tinged with brown, oval or oval-lanceo- 

 law, 2-4-flowered, 5-6 mm. long, joint of rachilla 0.7 mm. long; 

 empty glumes subequal, ovate-lanceolate or oval-lanceolate, 3-nervcd, 

 second 3.5-4.2 mm. long; floral glume 3.2-4 mm. long, thin, spar- 

 ingly webbed at base, pubescent on the marginal nerves and the 

 lower half of the keel, oval, obtuse, subacute, emarginate or erose 

 with an extended scarious apex; palea thin, 3-3.5 mm. long, ciliolute 

 on the keels. Nearly allied to P. alpina L. 



New Hampshire, Faxon; Vermont, Hosford tor U. S. Dept. 

 Agricul. 654, Pringle. 



New England to Eocky Mountains and well northward ; also in 

 Europe. In Hooker's Flor. Bor. Am. this is treated as P. Jlexuosa. 



40. P. gracillima Vasey, Contrib. U. S. Nat. Herb. 1 : 272 

 (1893). 



A slender, densely tufted perennial, 30-50 cm. high, the upper 

 node extending one-fourth or less than the len,7:th of the culm. 

 Blades of sterile shoots tliin, smooth, acute, flat or conduplicate, 

 filiform, 5-10 cm. long, 0.6-1 mm. wide, those of the cnlm 2 ; 

 ligule 2.5 mm. long. Panicle open, pyramidal or ovoid, 5-8 cm. 

 long, rays scabrous in twos to fives, the longest 3-5 cm. long, bear- 

 ing 3-4 spikelets on the outer third. Spikelets tinged with violet, 

 oval or ovate-lanceolate, 3-5-flowered, 6-10 mm. long, a long joint- 

 er rachilla 1.5 mm. long; empty glumes oval-lanceolate, 3-nerved, 

 flrst 3-4 mm. long, second 3.5-5 mm. long; floral glume elliptical^ 

 8-5 mm. long, 5-neryed, subacute or obtuse with a wide scarious tip,. 



