482 PHANEROGAMOUS PLANTS. 



ate. Panicle 1 to lb inches long; rays mostly in pairs, one about 

 equalling the flower, and the other twice its length. Glumes 2 inches 

 long, obtuse and mucronate, puberulent, turning purplish with age, 

 about one-fourth shorter than the floret, which has a rounded callus 

 with a few short hairs. Lower palet one-nerved with scattered hairs 

 and minutely puncticulate, bearing just below its apex a slightly 

 twisted somewhat persistent awn about its own length ; upper palet 

 as broad as and slightly longer than the lower, faintly 2-nerved and 

 strongly involute. Stamens three, bearded at the apex. Styles three, 

 elongated and exserted. Squamulse two, as long as the ovary, inequi- 

 lateral. In two florets three styles were distinctly made out, but the 

 specimens were generally too mature to enable us to determine if this 

 is a constant character. 



This species, which we have seen only in the collections of the 

 Expedition, is most nearly allied to 0. Canadensis, from which it 

 abundantly differs in its simple and contracted panicle, its shorter 

 glumes, and in its awn. 



11. ST I PA, Linn. 



1. Stipa eminens, Gav. 



Stipa eminens, Cav. Icon. 5, p. 42, t. 467, fig. 1. 



8. mucronata, H. B. K. Nov. Gen., & Spec. 1, p. 103. 



Hab. North branch of the Columbia. — The collection contains the 

 panicle only of what agrees with a specimen determined as belonging 

 to this species by General Munro. It chiefly differs from the related 

 S. setigera, Presl, in having the lower palet hairy all over. 



2. Stipa yiridula, Trin. 



Stipa viridula, Trin. in Act. Petrop. 1836 ; Trin. & Ruprecht, Stipese, p. 57. 



8. parviflora, Nutt. Gen. 1, p. 59. 



8. spartea, Hook. Flor. Bor.- Am. 2, p. 37. 



S. Nuttalliana, Steud. Syn. Glum. 2, p. 643. 



Hab. Nisqually, north branch of the Columbia River, &c. 



