Source: C.Michael Hogan Quercus durata Jeps. (1909) The Leather
Oak, a California endemic, occurs primarily in the California
interior chaparral and woodlands ecoregion. It is a species with
strong affinity for ultramafic soils, a geochemical class of
high magnesium, low calcium and nutrient deficient media. In
appearance this is a shrub-like tree whose leathery leaves
reveal its common name and obvious membership in the sclerophyll
vegetation category, a morphological class of hard leaved
species that may occur in such diverse places as Australia,
Southern Africa, the Chilean Matorral and the Mediterranean
Basin as well as the California Floristic Province. Q durata has
two recognized varieties: * var. durata, occurs at elevation 150
to 1500 m in the California North and South Coast Ranges, San
Francisco Bay Area and northern Sierra Nevada foothills. Upper
leaf sufaces of this variety are severely convex * var.
gabrielensis occurs at elevation 450 to 1000 m as a limited
distribution taxon in the San Gabriel