Vegetation of 40 sample stands on serpentine soils was analyzed and used to indicate conditions that might limit the establishment of annual range species. Two groups of stands, “cypress” and “non-cypress,” were defined by cluster analysis. Stands with Cupressus sargentii also contained Arctostaphylos viscida and occurred on mesic sites with lower Ca in the sub-surface soil. Stands without C. sargentii usually contained Adenostoma fasciculatum and Quercus durata and occurred on the drier sites with higher Ca.

Principal component analysis was carried out on the vegetation data in each group of stands, and simple and partial correlations were calculated between principal components and environmental variables. A moisture gradient within the cypress stands was associated mainly with the water-storage capacity of the soil. Cupressus sargentii was more abundant at lower water-storage capacities (and at lower elevations), while Arctostaphylos viscida was most abundant at the opposite end of the gradient. No correlations were found with soil chemical analyses.

The relations between principal components and environmental variables were less apparent within the non-cypress stands. Adenostoma fasciculatum and Garrya congdoni were most abundant where Ca contents in the soil were high while Ceanothus jepsonii, Quercus durata, Bromus laevipes, and Sisyrinchium bellum were most abundant at the opposite end of the gradient.