Page:Popular Science Monthly Volume 79.djvu/555

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551
DESERT PLANTS

the heavy fogs of the California coast are in this way a source of supply for Cakile and other halophytes. In none of these cases, however, is the existence of the plants concerned so dependent upon atmospheric absorption

PSM V79 D555 Carnegiea gigantea partially dead is bearing flowers.png
Fig. 4. A Sahuaro (Carnegiea gigantea) of which the Main Stem has been Dead for over a Year, with three living branches, one of which bore flowers.

as has been found by Professor Peirce for the lichens which thrive in the fog channels leading up the valleys and over the passes along the Pacific shore.

Any study of this subject leads in the end to a consideration of the