The primary vegetation is a creosote bush community with barrel cactus (Ferocactus cylindraceus), Joshua trees (Yucca brevifolia), various chollas (Cylindropuntia spp.) and prickly pears (Opuntia spp.). Unlike other mountain ranges in Clark County, the McCullough Range is volcanic in origin. Examples of lava flows, ash falls and glassy zones are clearly visible. The area supports native black gramma grass (Bouteloua eriopoda), which is not known to occur anywhere else in Nevada and stands of teddy bear cholla (Cylindropuntia bigelovii), which is the northernmost extent of the species. Remarkable petroglyph panels and other important cultural resource features occur within the wilderness area.