PLATE IV.—Microscopic characters of the Alternaria; (a) mycelial threads 
within a cell from rotting pear; (b) hyphm showing the variable size of the 
mycelium; (c) mature spores from a culture; (d, e) manner of spore-formation 
from 'culture; (f) two spores germinating in”water, at the end of three 
hours. 
