The vegetation in Yosemite contains at least 1,374 vascular plant species along with numerous bryophytes and lichens. A total of 109 plant species have status as either a federal species of concern, listed as rare by the State of California, or listed by the park as rare.
There are six federal species of concern - three-bracted onion (Allium tribracteatum), Yosemite woolly sunflower (Eriophyllum nubigenum), Congdon’s lomatium (Lomatium congdonii), Tiehm’s rock-cress (Arabis tiehmii), slender-stemmed monkeyflower (Mimulus filicaulis), and Bolander’s clover (Trifolium bolanderi) - that are former Category 2 species under the Federal Endangered Species Act. Although Category 2 was abolished in 1996, species of concern is an informal term that refers to those species that might be declining or be in need of concentrated conservation actions to prevent decline. Therefore, these six species continue to be evaluated and managed by the National Park Service.
Mountain lady's slipper, Cypripedium montanum, is one of many rare plants in Yosemite National Park. Photo by Raye Santos/NPS.
Four state-listed rare species - Yosemite Onion (Allium yosemitense), Tompkin’s sedge (Carex tompkinsii), Congdon’s wooly sunflower (Eriophyllum congdonii), and Congdon’s lewisia (Lewisia congdonii) - are considered restricted and limited throughout all or a significant portion of their range, and may represent disjunct populations at the extreme end of their range.
The remaining species on this list are classified by the park as rare. These species are rare in the park but have no other status (either state or federal). Many of these species have extremely limited distributions in the park and may represent relict populations from past climatic or topographic conditions, while other species may be at the extreme extent of their range in the park or represent changes in species genetics.