Abstract

The vegetation of the Henry Mountains is unique. The flora is influenced by its proximity to the diverse floras of the Great Basin, the high Utah and Colorado plateaus, the southern Rocky Mountain ranges, the Navajo basin, and the Mojave Desert.

Geology is a controlling factor. Weathering and erosion of the alternating sandstone and shale of the Mancos Shale, whose thick deposits dominate the foothills section of the Henry Mountains, have resulted in a distinctive series of badlands and mesas. Along the southern and eastern boundaries of the Henry Mountains, deep canyons, adjacent slickrock, and low warm sand deserts provide a major migration pathway from southern vegetative types. The peaks support montane and alpine vegetation. Varied physiography and the great elevational and precipitational range provide environments suitable for many communities and for nearly every major vegetational zone that occurs in Utah. Species known only from the Henry Mountains are Astragalus henri-montanensis, Eriogonum cronquistii, and Pediocactus winkleri.

Isolated by distance and by terrain difficult to traverse and difficult to settle, the vegetation of these mountains is incompletely described. Study of the flora of the Henry Mountains area has much to reveal relative to phenomena of plant distribution, migration, endemism, and speciation.