MOULDS, EUSTS, ETC. 109 



IX. MOULDS, RUSTS, ETC. FUNGI.i 



MATERIAL KEQUIEED. 



Common black mould in difierent stages of development. Zygospores 



of any of the brown moulds. 

 Rust of wheat, some specimens having uredospores, others with teleu- 



tospores. The Eecidium form on barberry leaves. 



BLACK MOULD. Rliizopus nigricans, Ehr. 



I. Make preparation for the study two or three days in 

 advance by wetting pieces of bread and placing them on 

 a plate under a bell-jar. The mould will soon make its 

 appearance if the bread is kept moist and the bell-jar is 

 left undisturbed. It may also be found on many decaying 

 vegetable substances, such as sweet potatoes, squashes, and 

 the like. 



II. Observe the fungus in different stages of its devel- 

 opment, noting in its earlier growth the delicate white 

 filaments, hyphae, growing over the bread, some of them 

 penetrating it and others rising into the air. 



III. At a later stage observe the changes that take place 

 in the hyphae that rise above the surface of the bread, 

 sporangiophores. Notice 



1. The change of color at the ends of the sporangio- 



phores. What is the color of the oldest ones ? 



2. Increase of size and change of form. The swollen 



apical part is the spore-case, sporangium. 



1 General references : DeBary, Morphology and Biology of the Fungi, 

 Mycetozoa, and Bacteria ; v. Tavel, Vergleichende ilorphologie der Pilze. 



