CHAPTER VI 



THE FUNGI IMPERFECTI 



Besides the true Ascomycetes there are a large series of forms 

 that are analogous in some cases to the known conidial stages of 

 ascomycetes. Some of these are undoubtedly the conidial form or 

 stage of some ascomycetous species, but the relation between coni- 

 dial and ascosporic forms has not yet been discovered ; others 

 may at some time have been thus connected but having become 

 perennial they have lost their ascomycetous form ; others still are 

 without doubt perfect species whose relations have not yet been 

 determined. The species classed in this extensive group are ar- 

 ranged in three orders as follows : 



1. Conidia in perithecia-like cavities (pycnidia). I. Sphaeropsidales. 

 Conidia superficial, borne on loose or innate hyphae ; no pycnidia. 2. 



2. Hyphae innate with the matrix 2. Melanconiales. 

 Hyphae somewhat superficial, often floccose. 3. Moniliales. 



Except in the case of certain genera of leaf parasites, and a few 

 species injurious to cultivated plants, no considerable amount of 

 study has been given to the American species of these orders. 

 Our knowledge of them consists of miscellaneous descriptions of 

 species whose characters have never been compared with each 

 other. The added difficulty exists in these orders, that many of 

 its members are only stages in the life history of some fungus ex- 

 isting under another name. This relation is difficult to discover 

 and must be discovered often by a combination of culture experi- 

 ments with a careful study of its occurrence in the field. While 

 we know that many of these so-called genera are merely 

 form-genera, we are obliged to treat them as we do other genera 

 until the true relations of their last remaining species has been 

 worked out. It would be a valuable aid to their study if com- 

 piled descriptions even of American genera and species were ac- 

 cessible to students. As it is, we are practically forced to rely on 

 a Latin compilation not only of the American species but all the 



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