GENERAL REPORT. ° 
which they possess under the double guard of villosity and contraction. I 
am aware that Mr. Watson, in his most valuable report on the Botany of 
the Fortieth Parallel, is prepared to admit a large evaporation from the 
more succulent portions of the plant. 
The monotonous character of the flora of the drier regions does, in 
some measure, disappear, when, on examination of these plants, so uniform 
in general appearance, we find a large number of genera and species differ- 
ing from one another by the small amounts compatible with their surroundings. 
This (the surroundings) in part accounts for the predominance of some 
orders and often of genera. We find a somewhat similar condition of things 
in the centre of greatest development of the Proteacee in Australia, or of the 
Pelargoniums in South Africa. 
Comparatively few of our Eastern plants are found in these open grounds, 
and where one does occur it is apt to be a cosmopolitan weed, whose pliant 
constitution adapts it to any condition of life, as well as to the hostility of 
man. Polygonum aviculare and Chenopodium hybridum are examples. Among 
the exceptions to this statement is Ranunculus Cymbalaria ; but its natural 
habitat on the Western open lands is, by choice, alkaline soils, where, for a 
portion of the year at least, it can obtain moisture, just as with us it fre- 
quents salt-marshes and the sea-shore. 
Among the mountains, on the contrary, we find a larger number of 
familiar plants. Indeed, the list is so large that it would bea real labor to 
begin the enumeration. Those plants embraced under the common name of 
weeds are from necessity found usually on the roadsides and about habita- 
tions, just where they can be transported by human agency, and find, among 
other essentials, water. It is wonderful with what rapidity they have occu- 
pied the ground in many places. 
FLORA OF THE MOUNTAINS. 
Leaving the level ground, we at once come fairly within the range of 
the timber. In South Park, this is not far from 10,000 feet altitude : tongue- 
like projections of trees do extend lower down; but I refer to the main body 
of the forests. 
At Twin Lakes, the timber begins at about 9,500 feet. In the San Luis 
