46 



FUNGI 



been exposed to the air. It is readily obtained by exposing 

 moist bread to the atmosphere, and covering it with a dish 

 in order to keep it moist. Under these conditions rhizopus 

 will develop within a few days. 



Morphology. That plant body consists of slender, thread- 

 like, colorless, branching filaments called the mycelium. 



FIG. 15. Fungi. Bread mold (Rhizopus nigricans) showing young plant 

 at the left and a stolon with young subterranean hyphse and an aerial 

 hypha. 



Each branch of the mycelium is called a hypha (plural 

 hyphce). The hyphse which grow into the bread or other 

 media are called the subterranean hyphae. They function as 

 holdfast organs and as organs of absorption. Other branches 

 grow up into the air and are called aerial hypha?. At this 

 stage of development the hyphse are not divided by cross- 

 walls but the entire mycelium is a greatly branched one-celled 



