GENEEA OF GRASSES OF THE UNITED STATES. 121 
5. AGROSTIDEAE, THE TIMOTHY TRIBE. 
53. Calamagrostis Adans. 
Spikelets 1-flowered, the rachilla disarticulating above the glumes, 
usually prolonged behind the palea as a short, commonly hairy bristle ; 
glumes about equal, acute or acuminate ; lemma shorter and usually 
more delicate than the glumes, the callus bearing a tuft of hairs, 
which are often copious and as long as the lemma, awned from the 
back, usually below the middle, the awn being delicate and straight, 
or stouter and exsertecl, bent and sometimes twisted; palea shorter 
than the lemma. 
Perennial, usually moderately tall or robust grasses, with small 
spikelets in open or usually narrow, -sometimes spikelike panicles. 
Species over 100, in the cool and temperate regions of both hemi- 
spheres ; 26 species in the United States, mostly in the western moun- 
tains. 
Type species: Arundo calamagrostis L. 
Calamagrostis Adans., Fam. PI. 2: 31, 530. 1763. Adanson describes no 
species but in the index there is given under Kalamagrostis Diosk., three names 
or citiations, Negil. Arab., Gramen. Sheuz. t. 3. f. 5., and Arundo Lin. The 
reference to Scheuchzer is found in Linnseus's Species Plantarum under Arundo 
calamagrostis (1: 82), which consequently is the type of Calamagrostis. 
Deyeuxia Clarion; Beauv., Ess. Agrost. 43, pi. 9, f. 9, 10. 1812. Type, D. 
montana, the first of the two species figured. 
Amagris Raf., Princip. Fondament. Somiologie 27. 1814. A new name pro- 
posed for Calamagrostis, because that is formed of two other names. 
Athernotus Dulac, Fl. Hautes Pyr. 74. 1867. Based on " Calamagrostis Ad." 
Lunell 1 uses this name for Calamovilfa, but Dulac bases the genus on Cala- 
magrostis Adans., and the three species he includes belong in Calamagrostis, 
not in Calamovilfa. 
By some authors the species with prolonged rachilla are segregated 
as a distinct genus, Deyeuxia, the name Calamagrostis being retained 
for those species in which the rachilla is not prolonged. The Ameri- 
can species all belong to the section Deyeuxia. 
Four Pacific coast species have loose, open panicles. In all the 
other species the panicle is rather compact, in some cases spikelike. 
The commonest species in the United States is Calamagrostis cana- 
densis (Michx.) Beauv. (fig. 64), growing in swamps and low ground 
from New England to Oregon, and southward in the mountains and 
northward to the arctic circle. It is an important source of wild hay 
from Wisconsin to North Dakota, but is of only medium value for 
grazing. Much of the marsh hay of Wisconsin and Minnesota be- 
longs to this species, which in that region is called blue joint. This is 
the dominant grass in the interior of Alaska. The species is distin- 
guished by having flat blades, a somewhat lax, usually nodding 
panicle, the hairs at the base of the floret copious and as long as the 
lemma, the awn straight, delicate, not exserted beyond the glumes, the 
latter 3 to 5 mm. long. 
3 Amer. Midi. Nat. 4: 218. 1915. 
