130 BULLETIN 772, U. S. DEPARTMENT OF AGRICULTURE. 



This is an important range grass. Common on the Pacific slope is 

 A. diegoensis Vasey, with creeping rhizomes, spreading panicles, and 

 often awned spikelets. 



Two native species belonging 

 to the group in which the palea 

 is lacking are common in -the 

 eastern United States. Agrostis 

 perennam (Walt.) Tuckerm. is 

 a woodland species with open 

 panicle. Agrostis hiemalis 

 (Walt.) B. S. P. (fig. 68) is a 

 delicate open-ground species 

 with very diffuse capillary pani- 

 cle, which at maturity breaks 

 away from the plant as a tumble- 

 weed. This species, called hair- 

 grass and tickle grass, is found 

 throughout the United States. 



Agrostis spica-venti L. (fig. 

 69), a European species, sparingly introduced in the Eastern States, 

 has been made the type of a distinct genus, Apera, being distinguished 

 by the prolongation of the rachilla and the long delicate awn from 



FIG. 68. Tickle grass, Agrostis 

 hiemalis. Plant, X \ ', spikelet 

 and floret, X 5. 



