Coast Dudleya

This plant is common and is found along the coast of California. Because the delimitation of the plant is based on arbitrary characteristics, the exact biogeographical distribution is difficult to pin down. The 2012 Jepson Treatment places the northern limit on the southern North Coast of the California Floristic Province. Plants identified with Dudleya caespitosa are found in the north from Point Reyes south to Malibu.

On the central coast of California near Santa Maria, numerous oil refineries exist, pumping phytotoxic sulfur dioxide. While plants like Salvia mellifera (black sage) were affected, Dudleya caespitosa proved to be somewhat tolerant of the emissions. This is likely due to the fact that Dudleya caespitosa uses CAM photosynthesis, which means their stomata open in the evening hours. Combined with the effect of southeast winds at night that blow away the emissions, the Dudleya avoid the phytotoxic emissions through this combination of meteorological conditions and CAM photosynthesis.

The plant was first described in 1803 by Adrian Hardy Haworth as Cotyledon caespitosa (the basionym). The original text erroneously cited it as from the Cape of Good Hope. The same species would later be described again as Sedum cotyledon by Joseph Franz von Jacquin and as Cotyledon linguiformis by Brown, both in 1811. In 1849, Lindley described the plant as Echeveria laxa, noting it as a very distinct looking plant, "but not one that is handsome." The plant was described in its current form by Nathaniel Lord Britton and Joseph Nelson Rose in their revision of North American Crassulaceae, which created the genus Dudleya.