22 The North American Cup-Fungi 



suring sexual reproduction. It is easy to conceive that they 

 might serve this purpose. 



While asexual reproduction by means of conidia is com- 

 paratively rare in the present group, so far as our present knowl- 

 edge goes, some are readily reproduced from spawn. This is 

 especially true of the coprophilous forms. The dried substratum 

 with the spawn can be kept dormant for long periods, while 

 growth is resumed almost immediately on being restored to 

 moist conditions. 



Fig. 12. Bolrytis type of asexual spores reported by Dodge 

 for Patella abundans. 



13. Ecology 



With a few possible exceptions, the plants of this group are 

 all saprophytic, although it is not easy to determine absolutely 

 whether a fungus is parasitic or saprophytic without extended 

 investigation. A few species of operculate cup-fungi which 

 appear on dead foliage may have been parasitic on the living 

 host, coming to fruit only after its death. Pithya Ciipressi on 

 the foliage of certain evergreens might be cited as one of this 

 type. Also Humarina axillaris grows in the axils of the leaves 

 of a moss and Humarina ithacaensis on the thallus of a liverwort. 

 The great majority, however, are strictly saprophytic, growing 

 on all kinds of decaying material, especially vegetable humus. 



Even saprophytes are often very selective in their habits or 

 tastes and grow only on certain types of decaying material. 

 Several species of Humarina grow only on the humus of decaying 



