An account on Danish SLil)nierse Freshwater 

 Pliycomycetes, witli systematical remarlvs. 



(Abstract from the preceding paper.) 

 Studies on submerse Phycomycetes I. 



By 



Henning E. Petersen. 



(Copenhagen.) 



During several years I have been occupied with the study of the 

 submerse Phycomycetes. Partly I have made collections of these fungi in 

 Denmark and thereby gained knowledge of their morphology, biology and 

 distribution, partly I have made experiments with species of Saprolegniacea? 

 for proving the general validity of Klebs's experiences in Saprolegnia mixta. 



Formerly I have published two papers on these fungi 1. Note sur 

 les Phycomycetes observes sur les teguments vides des nymphes de Phryga- 

 nees etc. Journal de Botanique 1903 and 2. Contributions a la connais- 

 sance des Phycomycetes marins, Oversigt over det kgl. danske Vidensk. 

 Selskabs Forhandlinger 1 905. In the following I shall publish my studies 

 from the last years. 



This paper contains at first remarks on the system of the Phy- 

 comycetes. 



As well known the oldest view of the phylogeny of the Chytridineae 

 thought these formes to be descending from the higher organized Phycomy- 

 cetes or certain groups of Algae. This view is given by de B a r y and 

 Sachs. Later an opposite view has been proposed. In 1883 Dangeard 

 finishes a paper upon the Ghytridinese with remarks on the relationship 

 between Monadinae and these forms. In Rabenhorst's Kryptogamenfiora 

 A. Fischer defends the same idea of the Ghytridineae as Archimycetes 

 descending from such primitive forms as the Monadina^. 



In the last years two papers on this subject were published by 

 Dangeard^) and Vuillemin^). Dangeard is the constant adherent of 

 the Monadine-hypothesis. Vuillemin on the other hand is, so far I can 

 understand him, of opinion that the two-flagellated ChytridineEe and other 

 Phycomycetes may be derived from other Phycomycetes or certain Algae 



^) Les ancfetres des champignons superieurs; le Botaniste, 9e serie, 1906. 

 ^) Les bases actuelles de la systematique en mycologie. Progressus rei bot. 

 Bd. IL H. 1. 1907. 



