2 5 



GENERAL MORPHOLOGY OF PLANTS 



and might be mistaken for the sporangium after the spores are 

 scattered. It sometimes collapses as shown in fig. 209. At the 

 base of the clusters of sporophores is a tuft of delicate, branched, 

 rootlet-like threads called rhizoids. These as well as the sporo- 

 phores become blackish in color. The larger number of these 

 clusters of sporophores are borne at intervals on distinct creeping 

 hyphae, which rise into the air and then touch the substratum 

 here and there like the stolon of the strawberry vine, or the leaf 

 of the walking fern, developing a cluster of sporophores at each 

 point of contact. These stolon-like hyphae will spread off from 

 the bread onto the sides of the vessel. Because of this peculiar 

 stolon-like hypha this mold is sometimes called the stolon bearer 

 (Mucor stolonifer, another technical name sometimes applied). 

 The name Rhizopus is given to the plant because of the rhizoids at 

 the foot of the sporophores. 



404. Germination of the spores and character of the 

 mycelium. The spores germinate when the temperature and 



Fig. 210. 

 Spores of Mucor, and different stages of germination. 



moisture conditions are suitable. They absorb water and swell 

 to a large size, then a protuberance appears on one side, which is 

 the beginning of a hypha or mycelial thread. This is called the 

 germ tube, because it resembles a short tube from the germinating 

 spore. This elongates quite rapidly, and branches profusely, 

 sending branches radially in all directions in the food substance, 

 and others into the air if the air is moist. The mycelium is con- 

 tinuous, i.e., it is not divided up into cells by cross walls, The 



