Cold, dry desert, dominated by shrubs such as sagebrush and saltbush, and grasses

Warm, subtropical desert with twice-yearly rainfall. Dominated by creosote bush, but with many large cacti and nitrogen-fixing trees in upland regions where the soils are deeper

Transitional between the Great Basin and Sonoran desert, but with some distinctive plants such as the Joshua tree in upland regions. Receives winter rainfall.

Characterised by hot summers (with summer rains), cold winters and lime-rich soils. Contains many small cacti and cold-tolerant plants such as agaves and yuccas.