ON THE SEXUALITY OF THE FUNGI, 271 



There is little need to dwell on this scheme, since its chief 

 interest for us is in its being an intelligible attempt to classify 

 the Fungi from the point of view of the theory of descent. A 

 point of some importance, however, may be referred to, as we 

 shall have occasion to speak of it later. Brefeld indicates the 

 possibility that the Oosporese (typified by Peronosporese) 

 may be allied to the '' true Fungi " otherwise than by a common 

 descent from some Alga-like ancestor. He also recognises a 

 common origin for the Oosporeae and the Zygomycetes. 

 In other respects the system is chiefly remarkable for the 

 peculiar views taken of the descent of the two great groups, 

 the typical Basidiomycetes (Gasteromycetes and Hy- 

 menomycetes, &c.) and the Ascomycetes, -which he regards 

 as having long ago diverged from a common point, at a time 

 when the ancestral forms commenced to specialise their repro- 

 ductive organs. "While on the one hand asci arose as spe- 

 cialised forms of sporangia — complications resulting from the 

 development of perithecia, &c., being considered unimportant 

 — on the other hand, the sporangia became degraded to conidia, 

 and the Basidiomycetes came to be merely highly developed 

 tufts of conidiophores. 



In a later memoir ^ Brefeld insists on regarding the so-called 

 pollinodia of the Ascomycetes as simply tubes for enve- 

 loping the ascogenous cell or filament ; and it is interesting to 

 note that he quotes Melanospora as a case where the non- 

 sexual relation of the ascogenous cell and the filaments which 

 envelope it may be clearly observed. Brefeld also points out 

 that in the Ascomycetes we can trace gradual degradations 

 of the various forms of fructification, with a disappearance of 

 sexuality at the same time. He supposes that all the Fungi 

 arose from an ancestral form containing chlorophyll and 

 possessing sporangia, and that the variations met with are derived 

 by modifications of this sporangium, as already indicated. 



It seems unnecessary to criticise these views in detail, since 

 it is obvious that no decision can be arrived at apart from the 

 consideration of numerous facts. It will be noticed^ however, 

 * * Schimmelpilze,' iv, 1881. 



