The environment in which a fungus grows is exceedingly complex has been demonstrated in a series of proposed outlines to be used in the study of ecological life histories of fungi. Pathogenicity of one fungus on another may be expressed in reduction of size of a fruit body, or in the elimination of the ability by the host to sporulate in favor of the parasite. Fungal and bacterial degradation of dead grass tissue yields ammonia and nitrate nitrogen which enable the grasses to grow more vigorously producing darker green leaves and larger growth. Fairy ring patterns may continue to develop indefinitely, probably showing a continuous and steady source of nutrients; clan patterns show a relatively limited developmental pattern in time, probably based on the elimination by the fungus of its food base.