PLATE 25 
Calvatia cyathiformis: 
A. —A ring showing stimulation of native plants inside the fruiting zone. The 
plants showing increased growth are the annuals Plantago purshii, Festuca octoflora, 
Lepidium ramossissimum, etc., and the perennial short grasses and Artemisia 
frigida. The fruits are well in advance of this stimulated zone. The advance 
here is from left to right. The second crop of puffballs is seen. Akron, Colo., 
August 16, 1915. 
B. —A trench through fruiting zone of C. cyathiformis . The soil is moist throughout, 
owing to recent rains. The mycelium can be distinguished with difficulty and does 
not render the soil impervious to water as does the mycelium of Agaricus tabularis. 
Fruiting bodies are seen about 30 cm. ahead of the stimulated area in which Plantago 
purshii shows greatest response. Akron, Colo., August 16, 1915. 
