ON THE SEXUALITY OF THE FUNGI. 275, 



corini and the Entomoplitliorese^ basing the conclusion 

 that Entoraophthora is a Zygomycete chiefly on Nowa- 

 kowski's description of the zygospores.^ It should be remem- 

 bered that Brefeld considers the resting spores of this genus as 

 arising asexually ; but that he, too, indicates the possible 

 alliance of the Entomophthoreae with the Oosporeae, and 

 therefore, indirectly, with Zygomycetes. 



Pythium seems closely allied to the Ancylistece of 

 Pfitzer,2 which lead us on to the Chytridese, in which we 

 meet with forms which conjugate (and are therefore sexually 

 simpler) as well as purely apogamous genera. It is not 

 improbable that among these latter the asexually produced 

 resting spores are really oogonia, a view already held by 

 Brefeld in other cases. 



De Bary raises the point of the possible alliance of these 

 simple parasitic Chytridiacese with the lower Algse (e.g. 

 Protococcacese), and decides that it is, on the whole, more 

 probable that they have been derived from the higher Fungi, 

 as indicated, by degeneration. 



The Ustilagineae are next dealt with. The author expresses 

 himself cautiously, but points out that this important and very 

 natural group may be looked upon as a series, beginning with 

 the simpler Entyloma, Tilletia, fee, and rising to more 

 complex forms, such as Sorisporium and Urocystis, on the 

 one hand, and Ustilago on the other. 



There are many difficult points to consider in classifying the 

 Ustilagineee. Their asexualh'- produced restiug-spores gene- 

 rally form a '' promycelium " on germination, from which 

 ''sporidia" arise; and, as is known, these "sporidia" com- 

 monly become united by cross-unions. But whether this is to 

 be regarded as a "copulation'-' or not, the sporidia often 

 germinate without it. It should be noted that Woronin^ 

 points out this significant fact also, and it is all but certain 

 that the so-called "copulation '^ is not of a sexual nature at all. 



> ' Bot. Zeituug,' 1877. 



- 'Mouatsber. der Berliu Akad.,' May, 1872. 



3 ' Beitr. zur Morpb./ R. v, 1882. 



