214 BOTANICAL GAZETTE ; [SEPTEMBER 
for San Jacinto, one of these mountains; the other, San Bernar- 
dino, yet awaits such detailed study. 
But as might be expected from the position of the mountain 
chain, narrow and between two hot and arid districts, the zonal 
differentiation is not here carried out to the extent, or with the 
distinctness, that is exhibited in mountains more favorably 
situated, and of greater area. Indeed, the commingling of the 
Hudsonian and Canadian with the Neutral (Pinus ponderosa) belt 
is a marked feature of these mountains. 
While, therefore, in a detailed study the separation of these 
zones may be preserved advantageously, it is more convenient 
for the purposes of a general view to unite the whole pine belt, 
which I propose to do under the name of the Nevadan area. 
Above it the Arctic flora is feebly represented; and by it the 
remaining territory is divided into two life-areas. The Desert 
area comprises the deserts north and east of the Nevadan Range; 
the district between that range and the sea may be designated as 
the Cismontane area. It remains to consider the character and 
limits of these several divisions, and of their subdivisions. 
THE ARCTIC-ALPINE ZONE. 
As has been stated already this zone is represented only on 
the summits of the two highest mountains, Grayback and San 
Jacinto. And it is but the scanty vestiges of an Arctic flora 
that lingers on these lofty summits, much scantier than their 
altitudes would justify one in expecting, even taking into con- 
sideration that this is the southern known limit of the Arctic 
flora on the North American continent. The summit of Gray- 
back is flat and consists of porous decomposed granite, unfavor- 
able to the growth of plants. San Jacinto is more fortunate, 
having on its precipitous northern face some steep, shaded 
cafions, preserving perpetual snows. But for all that, it does 
not exceed in species its less favored neighbor. A single species, 
Ranunculus Eschscholtzii, has been found on both peaks, Arenaria 
hirta verna and Antennaria alpina have been collected on Gray- 
back, while from San Jacinto Carex Preslii and Oxyria digyna 
This has been designated usually as the Intramontane area, but the present 
term seems preferable. : 
