MARIPOSA COUNTY AS A BOTANICAL DISTRICT. 
BY J. W. CONGDON. 
The botanical importance of Mariposa County depends upon two 
circumstances: st, that it isa fair representative of the mining and 
foothill counties west of the main chain of the Sierras, holding what 
may be considered an average position between the perpetual snows 
and heavy forest growths of Shasta in the north and the hot and 
comparatively low summits of the extreme south; 2dly, that con- 
taining, as it does, the Yosemite Valley and the Mariposa Grove of 
Big Trees, this county, or rather the mountain portion of it, has 
been largely visited and explored by botanists from all parts of the 
world. For that reason, I do not propose here to refer with any 
great particularity of detail to a region that has been so fully de- 
scribed. I shall, therefore, devote more space and attention to the 
less familiar portions of the county. 
The County of Mariposa, according to its general topographical 
features, may be considered as divided into about five zones or 
belts, each having its peculiar physical character and special vegeta- 
tion, the differences depending principally upon the altitude and — 
distance from the main chain. The “ Plains,” such as we see them 
in the central portions of Merced and other counties of the San_ 
Joaquin Valley, barely touch us on the western border and are not — 
here recognized as forming a separate district, as they would have 
to be in such counties as Merced and Fresno. ; 
Omitting, then, all separate reference to such scanty portions Of — 
the plain-land as we possess, the five zones above mentioned are: 
the lower or unwooded foothills, the wooded foothills, the coniferous — 
or evergreen belt, the subalpine region and the alpine summits. 
To these the valleys and cafions formed by the streams in their 
descent from the high mountains to the plains below, of which the | 
most noteworthy examples are the great Yosemite Valley, on the 
main Merced river, and the smaller Valley of the South Fork, at. 
Wawona, and Hite’s Cove, may be added as a sixth region, com- 
bining at least in their upper portions the floras of the different : 
zones through which they pass. os 
_ The unwooded foothills form the first outwork of the great chain 
of the Sierras, here nearly eighty miles wide on its western side. 
These foothills consist of irregularly grouped masses of more or 
