1d4 inches long and loosely flowered ; the spikelets are two-flowered; 
the outer glumes are about two lines long, the lower one one-nerved, 
the upper rather obovate and three-nerved; the lower flower is com- 
monly awnless or only tipped with a short awn; the second flower is 
rather shorter and with a slender, spreading awn longer than the flower. 
This is a nutritious grass, but is seldom found in sufficient quantity 
to be of much value. (Plate 55.) 
Trisetum subspicatum. 
The culms are erect and firm, smooth or downy. The panicle is spike-like, dense, 
and cylindrical or elongated, and more or less interrupted, generally of a purplish 
color. The spikelets are two or three-flowered. The flowers are a little longer than 
the outer glumes, slightly scabrous, the flowering glumes acutely two-toothed at the 
apex, and bearing a stout awn which is longer than its glume. 
A perennial grass of the mountainous region of Europe and North 
America; undoubtedly furnishes a considerable portion of mountain 
pasturage. It is found sparingly in New England, on the shores of 
Lake Superior, in the Rocky Mountains of Colorado, Utah, California, 
Oregon, and northward to the Arctic circle. It varies in height accord- 
= to the latitude at which it grows, being sometimes reduced to 3 or 
4 inches, at other times running up to 2 feet high. (Plate 56.) 
| AVENA. 
Avena fatua (Wild Oats). ; 
This species is very common in Calfornia. It is generally thought to 
have been introduced from Europe, where it is native, but it bas become 
diffused over many other countries, including Australia and Sonth 
America. It is thought by some to be the original of the cultivated 
oat, Avena sativa, that the common will degenerate into the wild oat, 
~ and that by careful cultivation and selection of seed the wild oat can 
be changed into the common cultivated oat. But on this question there 
is a conflict of opinions, and the alleged facts are not sufficiently estab- 
lished. The wild oat differs from the cultivated one chiefly in having. 
more flowers in the spikelets, in the long, brown hairs which cover the 
flowering glumes, in the constant presence of the long, twisted awn, 
and in the smaller size and lighter weight of the grain. It is a great 
injury to any grain-field in which it may be introduced; but for the 
purposes of fodder, of which it makes a good rut , it has been much 
‘employed in California. (Plate 57.) 
ARRHENATHERUM. 
Arrhenatherum avenaceum (Evergreen Grass; Meadow Oat Grass; Tall Oat Grass). 
Culms 2 to 4 feet high, erect, rather stout, with four or five leaves each; the sheaths 
-snooth, the leaves somewhat rough on the upper surface, 6 to 10 inches long, and about 
3 lines wide, gradually pointed. The panicle is Joose, rather contracted, from 6 to 10 
inches long, and rather drooping ; the branches very mmequal, mostly in fives, the 
longer ones 1 to3 inches, and aie aended from about the middle; the smaller branches 
very short, all rather full- flowered. The spikelets are mostly on short pedicels. The 
