Chap. YII. WILD CEEEALIA. 539 
far as the Gulf of Mexico, and on the other to the 
shores of the Pacific. The reader will have seen, from my 
description of the scenery, that the vegetation, apart from 
the general absence of trees, is of a greatly varied character. 
As we approached the slope of the continent toward 
the Pacific, the annual growth of grasses and herbs is 
an important feature in the vegetation ; but as soon as 
we cross the principal range of the Californian moun- 
tains — which seems to form a complete line of demarcation 
in reference to the meteorological character of the country 
— wild oats and wild clover cover hills and valleys almost 
exclusively for many hundred miles. The clover too — 
at least some species — is of annual growth, and its seed, 
which covers large extents of ground, forms for months 
almost the exclusive food of herds of cattle, which are 
numbered by thousands. The wild oats I saw in the 
south of California, and especially those on the hills behind 
Los Angeles, was as thick, as tall, and with as heavy ears 
as the finest cultivated oats in Europe. I found wild barley 
in the neighbourhood of "Warner's Rancho," far from 
the road or any human habitation, in a perfect wilderness. 
And lastly, I saw a sample of wild wheat at an agricultural 
exhibition at San Francisco, which was wonderfully fine ; 
but I could learn nothing more than that it came from the 
Sierra Nevada. I am thus tempted to call the climate of 
these parts, from the Gila, where the annual grasses begin, 
a normal .climate for cereals, exclusive of maize, for which 
California appears to be less adapted ; barley takes its 
place here, at least as fodder for horses and mules. 
The absence of trees in a large part of the North Ame- 
rican continent is an interesting point for inquiry to the 
botanist, climatologist and geologist. Throughout Cali- 
fornia the opinion prevails, that no trees can be grown in 
