292 THE ESSEX NATURALIST
in Ganoderma applanatum to 0.1 cm. in Tilletia
caries.
Fig. 2. Diagram of spore liberation in a cup-fungus (Humaria) and an
agaric (Collybia radicata).
The layer of air in close contact with the ground or with
any surface is non-turbulent, and spores liberated into this
layer quickly fall. Above this static zone the air is con-
tinually being mixed by eddies, and as these eddies diffuse
and become caught up by other eddies, the spores which