A BRYOPHYTE INVENTORY OF MOUNT DIABLO, CONTRA COSTA COUNTY, CALIFORNIA

Abstract

Mount Diablo in Contra Costa County is a notable peak in California's central Coast Ranges, well known for its biodiversity. To date, no accounts of the bryophytes on this mountain have been published. We present a catalogue of the mosses, liverworts, and hornworts known to occur on Mount Diablo. We base this on collections made by us and augmented by specimens from other collectors that are housed in North American herbaria. We collected extensively on the mountain from 2014 to 2020. Online databases were searched to locate specimens from Mount Diablo. These were located predominantly at the University of California Berkeley (UC) or California Academy of Sciences (CAS). Specimens were examined at these herbaria to confirm their presence and to confirm identifications as needed. We list 160 bryophyte taxa on the mountain, including 137 mosses, 20 liverworts, and three hornworts. Forty families and 75 genera are represented, with Pottiaceae having the most species (39). We list separately 22 taxa that we consider unconfirmed on Mount Diablo because they are represented only by herbarium specimens that we could not locate, or for other reasons as given. Our own collections added 19 bryophyte species (17 mosses and two liverworts) since 2014. We did not find 41 of the confirmed taxa reported on Mount Diablo by others. Thirty-three taxa have so far been collected only once on the mountain. These numbers imply that additional taxa occur there and have not yet been found. We discuss the distribution of taxa within different parts of the mountain, and the Mount Diablo bryophyte flora is briefly compared with that of neighboring regions and of California as a whole.