148 Descriptions of some new Grasses. 



Descriptions of some new Grasses collected by Dr. E.- 

 James, in the expedition of Major Long to the Rocky 

 Mountains, in 1819 — 1820. By John Torrey. Read 

 May 17th, 1824. 



In a former part of this volume, I commenced an account 

 of the alpine plants collected in this expedition, by Dr. James, 

 which I promised to continue, in occasional decades. Having 

 been obliged, for the present, to defer the examination of the 

 remaining specimens, I beg leave to offer to the Lyceum descrip- 

 tions of some new grasses, collected by Dr. James in the same 

 expedition. Their number might have been considerably in- 

 creased had not many of them been discovered a short time 

 previous, by Mr. Nuttall, in his Travels into the Arkansas Ter- 

 ritory. One species, of which there were very perfect speci- 

 mens, in the herbarium of Dr. James, is so peculiar that I 

 have proposed it as the type of a new genus, under the name 

 of Pleuraphis. 



Pleuraphis.* 



Gen. ch. Flowers spiked, heterogamous. Spikelets three 

 at each joint of the rachis, all sessile, surrounded at the base 

 by a villous involucrum. Central spikelet perfect. Calyx 

 two-glumed, one-flowered ; glumes obcuneate, two-cleft, five- 

 bristled. Corolla two-valved, hyaline ; inferior valve with a 

 short bristle. Lateral spikelets antheriferous. Calyx two- 

 glumed, two-flowered ; inferior glume with a bristle on one 

 side near the base. Corolla two-valved, unarmed. 



1. P. Jamesii.* PI. X. 



DESCRIPTION. 



Root perennial, creeping. 



Culm cespitose at the base, about a foot high, terete, smooth, 

 slender. 



