130 BULLETIN 772, U. S. DEPAKTMENT OF AGKICULTUKE. 
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 
perennans (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 
MemaKs. Plant, X 
and floret, X 5. 
Agrostis 
spikelet 
