North American Warm Desert Volcanic Rockland

Geology

Tertiary extrusive igneous formations, including tuff, basalt, and rhyolite.

Landform

Usually talus slopes, but also relatively level rocky and boulder sites.

Soils

Soil is generally lacking or reduced to small pockets within the rock matrix.

Parent Description

Very sparsely vegetated sites (<10% cover) on rocky or boulder strewn slopes and flats where the rock material is volcanic in origin. Scattered individuals of species such as Larrea tridentata (creosotebush), Fouquieria splendens (ocotillo), Jatropha dioica (leatherstem), Prosopis glandulosa (honey mesquite), Yucca torreyi (Torrey's yucca), and cacti such as Echinocereus spp. (hedgehog cacti) and Opuntia rufida (blind pricklypear) may be present.