XVI International Botanical Congess

Floristic studies of eukaryotic microalgae present in microbiotic soil crusts of North America have focused on the Great Basin and Sonoran deserts. Little information is available on the algae present in soils of the Mojave Desert. I examined ten composite soil samples collected from five distinct Mojave sites in California. Characterization of 10-40 individual isolates from each of these sites revealed the presence of over 30 different taxa representing 23 genera of non-diatom eukaryotic algae. Several of these taxa represent new species. Chlorophytes were recovered more often than xanthophytes. Among the chlorophytes, members of the genera Chlorella, Chlamydomonas, Myrmecia and Stichococcus were recovered in at least four of the ten sites. Chloridella and Monodus were the only xanthophytes recovered. Generic diversity at sites was low (3-7/site).