taxonomy, floristics, phycology, microbiotic crusts, cyanobacteria, Mojave Desert


The Fort Irwin National Training Center in the Mojave Desert of California contains soils that represent a diversity of disturbance regimes, including some soil sites that have been protected from anthropogenic disturbance for many years. Previous studies of the soils of this military installation discussed biogeography and ecology of the crusts but did not conduct detailed study of the species present. In this study, we selected 6 sites in and around the Fort Irwin Training Center to be the subject of intensive isolation efforts. These sites contained at least some development of microbiotic soil crust. Out of the more than 90 cyanobacterial isolates characterized, only 23 distinctive morphospecies were differentiated. Of these, only 13 were identified to a previously described species, the others being comparable to previously described aquatic species (cf.) or so dissimilar to described taxa that they were given numbers as identification. Leptolyngbya was the most species rich and also the most commonly isolated genus. Twelve filamentous genera were found; no coccoid representatives occurred in our samples. All taxa are described and illustrated. This study is significant as it is the first since the 1960s to examine cyanobacterial taxonomy of Mojave Desert soils in a systematic fashion. Our unidentified taxa are very likely new species but will require molecular sequence analysis before they can be named.