290 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 13 



There are many variations in this association. One form occurs on 

 terraces where the soil is much deeper and more finely textured than on 

 the canyon slopes. This terrace type forms the unique and remarkable 

 Coreopsis association which occurs on Santa Barbara and the eastern 

 island of Anacapa and was described in the preceding section. Isolated 

 plants of Coreopsis gigantea have been reported from each of the Channel 

 Islands, usually growing in inaccessible situations on rocky bluffs. The 

 eastern bluffs of Santa Catalina Island, those which are steep enough to 

 deter grazing animals, support a scattered growth of poorly developed 

 plants. A rocky hill near Empire Landing on Santa Catalina has the 

 largest colony of Coreopsis to be found on any of the larger islands 

 at the present time. 



The principal communities of this association are given in table 5, 

 with the main constituents of each community and their distribution. 

 Several species which are to be found in nearly every variation of the 

 coastal sagebrush are listed first. 



Maritime Desert shrub. The only desert shrub of the islands is 

 located on the southern third of San Clemente Island. On the higher 

 terraces it is composed almost wholly of Opuntia prolifera. On middle 

 terraces Opuntia littoralis and Cereus Emory i appear, while on the 

 lowest terraces other low shrubs enter into the composition, including 

 Lycium californicum, Artemisia calif ornica insularis, Encelia calif ornica, 

 Lotus argophyllus adsurgens. Euphorbia misera, and Castilleja grisea. 

 No record of the annual precipitation is available for this area but an 

 estimate of six inches is given in the section dealing with climate. 



Sea Bluff Communties 



Because of the great extent of the coast line in relation to the total 

 area of the Channel Islands the most diversified plant life is that of the 

 sea bluffs. These communities have received detailed treatment in the 

 preceding section. Similar habitat conditions exist on all the islands. 

 Plants of such genera as A triplex, Echeveria, Eriogonum, Astragalus, 

 Eriophyllum, Opuntia, Mirabilis, Polpodium, Lycium, and Achillea are 

 usually present, but the composition varies with different islands. A list 

 of the plants of these communities is given in table 5. 



The floristic combinations differ with almost every varitation of 

 slope angle and exposure. Yet there is a characteristic pattern of life- 

 forms where the sea is always in the immediate foreground. The soil 

 is usually shallow and rocky, and both the diurnal and the annual 



