38 THE LOWER FUNGI—PHYCOMYCETES 



the orders Chytridineae, Ancylistineae, Monoblepharidineae, 

 Saprolegnineae, and Peronosporineae, and (2) the Zygomycetes, 

 including the Mucorineae and Entomophthorineae. Fischer 

 recognizes three primary subdivisions, Archimycetes, Oomycetes, 

 and Zygomycetes. In the Archimycetes he includes the genera 

 incorporated by Schroter in the Chytridineae and Ancylistineae. 

 In erecting this group he emphasizes the fact that in these forms 

 mycelium is absent or poorly developed and sexual reproduction 

 uncommon. In both classifications, the separation of the 

 Oomycetes and Zygomycetes is based on the essential difference 

 in the sexual process, oospores being characteristic of the former 

 and zygospores of the latter. The two classifications differ 

 further in several minor respects. The Pythiaceae, included 

 in the Saprolegnineae by Schroter, are incorporated in the 

 Peronosporineae by Fischer, and the Monoblepharidineae of 

 Schroter are treated as a family of the Saprolegnineae by Fischer. 

 Generic limits in the two separations are not in all cases identical, 

 as will be emphasized in later pages. 



In recent years, two other taxonomic treatments of the Phy- 

 comycetes have appeared, which are sufficiently outstanding to 

 require special consideration. These have been presented by 

 von Minden (1911) and Gaumann (1926). The classification of 

 von Minden is intermediate in several respects between the 

 separations of Schroter and Fischer. While he does not recog- 

 nize the group Archimycetes, and his ordinal separations cor- 

 respond essentially with those of Schroter, he includes the 

 Pythiaceae in the Peronosporineae and in numerous other details 

 follows Fischer. His paper as a whole is the most modern of 

 the taxonomic treatments providing keys to families and genera. 

 Gaumann concerns himself chiefly with problems of comparative 

 morphology, and does not attempt a complete taxonomic sepa- 

 ration. He removes the Olpidiaceae, Synchytriaceae, Plas- 

 modiophoraceae, and Woroninaceae from the Phycomycetes 

 and treats them as a lower group to which he applies the name 

 Archimycetes. The Rhizidiaceae, Hyphochytriaceae, and Clado- 

 chytriaceae comprise the Chytridiales in his arrangement. 

 He divides the Phycomycetes into Chytridiales, Oomycetes, 

 and Zygomycetes. The Oomycetes include the Monoblephari- 

 daceae, Blastocladiaceae, Ancylistaceae, Saprolegniaceae, Lep- 

 tomitaceae, and Peronosporaceae. The Zygomycetes include 

 the Mucoraceae, Endogonaceae, and Entomophthoraceae. The 



