CHAPTER XII 



FUNGI IMPERFECTA 



The imperfect fungi, or fungi imperfecti, constitute an heter- 

 ogeneous subdivision of the true fungi. As a class it is not com- 

 parable to the natural classes thus far discussed, yet it may be 

 given an equivalent name and regarded as a coordinate division 

 for the sake of convenience in general treatment and classifica- 

 tion. The fungi »thus brought together consist of species hav- 

 ing hyphomycetous, melanconiaceous, or sphasropsidaceous types 

 of spore production. Since these types may represent special 

 " stages " in the life cycles of other fungi, these secondary fruit 

 forms in general will not permit of certain classification under the 

 groups thus far discussed, much less under the Basidiomycetes 

 subsequently treated. The great majority, however, and perhaps 

 all of those here discussed would unquestionably find their natural 

 relationships with various genera of the Ascomycetes, and for that 

 reason they are conveniently treated as following that group. 

 Some of the Hyphomycetes in general, however, might represent 

 imperfect forms of the Phycomycetes or even of the Basidio- 

 mycetes. In any case it would generally be impossible to de- 

 termine the genus or even the family in which a particular 

 imperfect fungus or form genus might be placed. It is therefore 

 essential to have such form genera, under which species may be 

 described and classified until their complete life cycles are known, 

 when they may be transferred to the proper natural genus (genus 

 of so-called perfect fungi). In many other minor ways the form 

 genus is a matter of convenience and certainly contributes some 

 stimulus for a better description of the different spore forms in 

 the polymorphic species. 



Among the imperfect fungi, as here interpreted, three chief 

 subdivisions are generally recognized, as follows : 



Hyphomycetes — conidia borne upon exposed conidiophores 

 which may be single, fascicled, or united together in a columnar 

 or tubercular fashion. 



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