DUST PLANTS . 
33 
MOLDS 
Another micro-organism which is seldom absent 
from house dust, either as the plant cell itself or its 
spore, is mold. This in our dust garden formed the 
:olonies with dark centers and a velvety pile. Molds 
FIG. 18. A GROWTH OF MOLD. 
Mycelium, Hyphae and Spore-cases. (After Jorgensen.) 
consist of vegetative portions which grow out in long 
threads, and these by budding and branching unite 
to form a network over the substance they are using 
as food. Fig. 18. 
From this network or mycelium grow out cells called 
hyhae set apart for special wprk—that of bearing the 
reproductive portion—the heads or stalked clubs. 
Inside these heads or from their outer surface 
Growth of 
Mold 
Reproduction 
