ALGAL COMPOSITION OF MICROBIOTIC CRUSTS FROM THE CENTRAL DESERT OF BAJA-CALIFORNIA, MEXICO

A total of 66 algal species representing 32 genera were recovered from soils of 10 sites in the Catavina region of the Central Desert of Baj a California, Mexico. The most common species encountered were the cya nophytes;Nostoc commune and Schizothrix calcicola, the chlorophyte Myr mecia astigmatica, and the diatoms Hantzschia amphioxys, Hantzschia am phyoxys f. capitata, Luticola cohnii, Luticola mutica, and Pinnularia borealis var. scalaris. Nine species not found in any previous studies of North American desert soils were present in our study sites, inclu ding 3 taxa new to science: Cylindrocystis brebissonii var. deserti, v ar. nov.; Elakatothrix obtusata, sp. nov.; and Fasciculochloris mexica na, sp. nov. Attempts to correlate species composition with soil chemi cal and physical parameters were unsuccessful apart from a pH effect o n cyanobacterial distribution. Overall composition of the soil algal c ommunity in the Catavina region is distinct from other desert sites we have studied, although some cosmopolitan desert soil taxa were presen t.