San Bernardino Valley

The trans-border flora of the San Bernardino National Wildlife Refuge in Arizona and Rancho San Bernardino in Sonora has 541 taxa in 316 genera and 86 families. The most diverse families are Poaceae (88 taxa), Asteraceae (84 taxa), Fabaceae (28 species), Euphorbiaceae (24 species), Amaranthaceae (18 species), Boraginaceae and Solanaceae (17 species each), and Brassicaceae (15 species).

On May 3, 1887, a major earthquake shook much of the southwest United States and Mexico, an area of nearly two million square kilometers. This seismic event, with an estimated magnitude of 7.2 (DuBois and Sbar, in press), caused 51 deaths in northern Sonora, and major destruction of property in southeast Arizona, as well as adjacent portions of Mexico. Moderate damage also occurred in New Mexico.