Great Basin Naturalist


A checklist of the vascular flora of the upper Walker River is presented. Listed are 1078 taxa from this 4000 km2 area. The upper Walker River encompasses a portion of the boundary between the Intermountain and Sierra Nevada floristic regions, and hence displays much floristic diversity within a relatively small area. Due to its location along the east slope of the Sierra Nevada, the Walker River drainage is unique in that it contains much elevational variation eastward into the Intermountain Region. This elevational extension is due to the presence of large mountain ranges including the Sweetwater Mountains, the Bodie Hills, and the Wassuk Range. As a result of this elevational variation, there is much overlapping of the two floristic regions. Additionally, the easternmost exposures of the Sierran granodiorites occur within the Walker River basin and may enhance the eastward migration of Sierran plants. The 90 percent floristic similarity (Sorenson's) between the Sweetwater Mountains, lying to the east of the Sierra, and the east slope of the Sierra Nevada (within the Walker River drainage) indicates the Sweetwaters to be more affiliated with the Sierran flora instead of the Intermountain flora.