Two Varieties of Monocillium Humicola in Wisconsin Forest Soils

SUMMARYA new variety of Monocillium humicola, M. humicola var. brunneum, is described. It differs from M. humicola var. humicola in its paler green surface and brown-pigmented reverse on honey-peptone agar, its less prominently roughened, lighter colored conidia, and in its occasional production of salmon to tan-colored sclerotia. Many cultures of both the new variety and M. humicola var. humicola were isolated from northern Wisconsin forest soils, but were found to peak in prominence in different segments of the vegetational continuum. Thus, 193 isolates of M. humicola var. brunneum were obtained primarily from dry and dry-mesic forest soils which supported Pinus banksiana, P. resinosa, and Quercus spp. as the dominants in the cover vegetation. M. humicola var. humicola was isolated primarily from wet-mesic and wet peat soils in communities dominated respectively by Thuja occidentalis and Abies balsamea, and by Picea mariana and Larix laricina.