THE ACRASIEAE IN NATURE. II. FOREST SOIL AS A PRIMARY HABITAT

Abstract

Although the Acrasieae are widely distributed in nature, they are most numerous and of the greatest variety in forest soils. Those species isolated from deciduous forest soils of Eastern and Midwestern United States belong to 2 families, the Dictyosteliaceae and Acytosteliaceae. Preference of the Acrasieae for forest soils over those of grassland was demonstrated by sampling a vegetational succession from prairie to forest. Occurrence of these slime molds within the forest soil profile is largely confined to the surface of the humus layer and the fermenting leaf litter. The Acrasieae are more numerous in forest soils in the autumn and spring than at other seasons. The frequency of occurrence of species varies considerably along the forest continuum of southern Wisconsin, indicating a differential response to microenvironments as influenced by the higher vegetation.