278 PART IV. CLASSIFICATION. 



There is no sexual process in the Schizomycetes, the Myxomy- 

 cetes, in some of the Phycomycetes (Saprolegniacese), the great 

 majority of the Ascomycetes, the vEcidiomycetes, and the Basidi- 

 omycetes. In the Schizomycetes and Myxomycetes, the absence 

 of a sexual process may be attributed to their rudimentary charac- 

 ter ; in the higher groups it is due to sexual degeneration. In 

 the Saprolegniacese, female and, generally, male organs are deve- 

 loped, but the male organs are functionless ; still the female organs 

 produce oospores. In the majority of the apparently sexual 

 Ascomycetes, even when both kinds of sexual organs are present 

 (e.g. Erysiphese, Penicillium, Sordaria) it is a question if any sexual 

 process takes place : yet in all these cases an ascocarp is pro- 

 duced, either from the female organ or from the mycelium. 



The sexual organs, with the exception of those of some Ascomy- 

 cetes, are unicellular. They are either quite similar to each other, 

 as in the Zygomycetes and some Ascomycetes (e.g. Eremascus), 

 when they may be termed gainetangia ; or they may be more or 

 less differentiated, as in the Oomycetes, and in some Ascomycetes 

 (e.g. Erysiphese, etc.), as male and female. 



The male organ is a pollinodium in the Oomycetes and in some 

 Ascomycetes (e.g. Pyronema, Erysiphese, Ascobolus) ; it is generally 

 unicellular but sometimes multicellular (e.g. Ascobolus). As it is 

 developed in close proximity to the female organ, fertilisation is 

 effected, in these forms, by absorption of the cell- walls at the 

 point of contact of the two organs, or the development of a tube 

 placing their cavities in communication. 



In some Ascomycetes (the Laboulbeniacese) non-motile male 

 cells (spermatia} are formed in unicellular antheridia. Spermatia 

 occur in other Ascomycetes, as also in the ^Ecidiomycetes, but 

 their sexuality has not been established in these cases. 



The female organ is either a unicellular closed oogonium (Oomy- 

 cetes), or a unicellular or multicellular archicarp (Ascomycetes). 

 The archicarp may consist (like the procarp of the Rhodophycese) 

 of two parts : a receptive portion, the trichogyne, which is a more 

 or less elongated multicellular filament, and a sporogenous portion, 

 the ascogoniuntj from which, after fertilisation has taken place, the 

 one or more sporangia (asci) of the ascocarp are developed. 



Sexual cells are only clearly differentiated in the case of the 

 female cells of the Oomycetes and of the spermatia of some 

 Ascomycetes. The female cells of the Oomycetes are oospJieres, 



