Vegetation of the Mohave and Colorado Deserts of southern California

Parish, S.

This paper discusses the geological, topographical, and plant ecological features of the Mojave Desert in California, which in the Pleistocene age was a great lake region draining in to the Death Valley and not connected to the sea. The desiccation of the once humid region has progressed so far that owing to the extreme heat and drought only plants of extreme xerophytic type can exist. Relatively few of the plants have organs adapted to water storage, the great majority depending upon structures which restrict evaporation or upon a rapid winter growth and a state of dormancy, mostly as seeds during the long rainless summers. Of the 454 species of typical xeropphilous phanerogams inhabiting the Mohave[sic], 282 are found also in the Colorado Desert and 263 do not extend into that region. Those genera common to both deserts are represented in each by different species. The similarity of soil and climate throughout the two desert areas accounts fully for the large identical flora; while the diversity, the author believes, is due to the mountainous barriers between them and to the different sources of origin, the Colorado Desert plants being derived from Lower California and the Gila district of Arizona, whereas the Mohave[sic] Desert plants belong to the flora of the Great Basin.

Vegetation of the Mohave and Colorado Deserts of southern California

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