FUNGI IMPERFECTI (p. 64) 



In the preceding pages it has been repeatedly evident that one 

 species of fungus may have two, even several different types of 

 spores; in the Erysiphales the perithecial form and the conidial; 

 in the Peronosporales oospores and conidia; in the Sphaeriales the 

 ascigerous form and several conidial forms; in the Basidiomycetes 

 the basidial form and various conidial forms; in the Uredinales 

 spring and summer stages and teliospores. In comparatively 

 few instances among the many thousand species of fimgi are all 

 of the different spore forms belonging to the species known to 

 man. In very many cases the lower or conidial forms are known 

 without any higher spore form (ascigerous, basidial, or sexual form) , 

 being known to be genetically connected with them, though it seems 

 very probable, reasoning by analogy, that these conidial forms 

 really constitute part of the life cycle of some fungus which em- 

 braces also a higher form of spore. It is probable, indeed certain, 

 that some of these conidial forms at present possess also higher, as 

 yet unknown, forms of fructification. It is likewise probable that 

 in many cases the conidial form, though it does not now possess 

 any higher spore form, did in its not remote phylogeny possess 

 such forms; indeed that all of them are phylogenetically related to 

 fungi which produced one of the higher types of spores. 



In some cases even in the absence of the higher spore it is possible 

 to refer the fungus to its proper order as for example is the case 

 with the conidial forms of the Peronosporales, the summer or spring 

 forms of the Uredinales, or the Oospora forms of the Erysiphales. 



Regarding many thousands of other conidial forms such refer- 

 ence is impossible or hazardous, since from the conidial form the 

 form of the higher spore can be inferred with only a small degree of 

 accuracy or not at all. For example, the conidial form known as 

 Gloeosporium in the higher form of some of its species proves to be 

 a Glomerella, in other cases a Pseudopeziza; some Fusariums 

 prove to belong to the life cycle of Nectria, others to that of Neocos- 

 mospora, etc. 



475 



