GROUPS OF PLANTS. 



25 



substance, ceridine. Other principles found in yeasts as well 

 as extracts are used in the treatment of cancer. 



Green and Yellow Mildews. To the Ascomycetes also 

 belong the green and yellow Mildews, Penicillium and Asper- 



Fig. 17. Penicillium, a green mildew. A, richly branching mycelium with conidio- 

 phores; B, enlarged view of conidiophore showing chains of conidia; C, D, E, F, success- 

 ive stages in the development of a perithecium; G, H, J, development of asci; K, groups 

 of asci containing from 4 to 8 ascospores; L, ascospores seen from the side and showing 

 characteristic markings. After Brefeld. 



gillus, so common in the household, the dairy, and the granary. 

 These plants produce profusely branching mycelia which form 

 patches upon or just under the surface of the materials upon 



