Corticolous Myxomycetes VI: A New Species of Diderma

Abstract

Corticolous Myxomycetes belong predominantly to only a few genera, for exalmple, Licca, Echinosteliiln, Macbrideola, and Badhanmia. Certain genera, such as Arcyria, Cribraria, Didermia, Didymizui, Heiiitrichia, Physaru,l, and Trichia, are well represented on terrestrial substrata (ground sites) or (lead parts of standing trees, both in frequency and numbers of species, but these same genera are represented by only two or three species on the bark of living trees. Members of the Physarales in general and Diderlma in particular often form extensive fruitings where a dense cover of mosses, liverworts, and lichens occurs on the bark surface. While there is undoubtedly a fair correlation between the total precipitation received during the growing season and the regional abundance of corticolous Myxomycetes, their abundance locally relates to factors affecting the proportion of time bark is supplied with adequate moisture. Our field observations indicate that there are local differences in the supply of moisture due to terrain and exposure to the elements. During periods of light precipitation only particular areas may become wetted,