272 H. MAESHALL WARD. 



that Brefeld's hypothesis assumes that, in addition to purely 

 vegetative modes of multiplication (e.g. the breaking up of 

 filaments, &c.), certain Fungi must have acquired other forms 

 of reproduction than those inherited and specialised — some 

 iEcidiomycetes, for instance, with their four kinds of spores 

 or spore-like bodies (aecidiospores, spermatia, uredospores, and 

 teleutospores) must have acquired at least one of these spores. 



At this point we may leave this short survey of Brefeld's 

 important work, and turn to the consideration of a memoir^ 

 published by De Bary about the same time as the last one 

 quoted. In this — probably the most important contribution 

 to mycology yet made — the author describes his observations 

 on the Perouosporese and Saprolegnise ; and bases upon 

 these and other previous observations a classification of the 

 Fungi which is in large measure new, and certainly promises 

 to be more fruitful than any yet proposed. 



De Bary finds that, passing from the typical Peronosporese 

 (Pythium, &c.) to the Erysiphese on the one hand, and to 

 the Saprolegnise on the other, the sexual process is gradually 

 eliminated, and the sexual organs become at first functionless 

 and then disappear altogether. In Pythium itself, the anthe- 

 ridium pierces the oogonium wall and fertilises the oosphere 

 by pouring protoplasm into it.^ In Phytophthora and 

 Peronospora the process is essentially similar, but the 

 quantity of protoplasm passed over from the antheridium is 

 smaller. 



In the Saprolegnise — which difi^er from Pythium and 

 other Peronosporese in forming several oospheres in each 

 oogonium — the fertilising tubes do not open, and no proto- 

 plasm can be observed to pass over from the antheridium to 

 the oospheres.^ Or, in some forms, no antheridia are present 

 at all — a fact already recognised by Pringsheim — and the 

 parthenogenetic spores are nevertheless capable of germinating. 



Now if the typical and thoroughly investigated case of 



' 'Beitrage zur Morph. und Phys. des Pilze, &c.,' R. iv, 1881. 

 ' Cf. ' Quart. Jouru. Mic. Sc./ October, 1883. 

 8 Cf. also ' Quart. Journ. Mic. Sc.,' July, 1883. 



