Observations on Saprolegniea. iq 



little notice in English publications, also to introduce the 

 study of American forms, and treat of some that have not 

 been described. 



According to Lindstedt (4,39), ^ the first mention of a form 

 belonging to this group, is by Ledermiiller, as early as 1760, 

 who noted a form of Saprolegnia, probably S. ferax grow- 

 ing upon a fly, and placed it among Confervaceae. Occa- 

 sional notices have since been made of them but the 

 most extensive memoirs are by M. Cornu (2) in French, 

 and H. Pringsheim in German (6), while among other writers 

 Hildebrandt (3), De Bary, Reinke (9), Lindstedt (4), Thuret 

 (8), have published various specific accounts. 



The Saprolegnieae are aquatic, parasitic, nearly colorless 

 plants, appearing to the unaided eye merely as a light 

 grayish, or white cushion-like mass of fine filaments. 



They were placed by early investigators (3) (5) (8) among 

 the Algae, chiefly on account of the resemblance of 

 their mode of reproduction to that in certain Algae, and 

 because they have also the same habitat. There is yet 

 a diversity of opinion as to their true position; but 

 later writers generally place them among the Fungi. I 

 made some experiments bearing on the determination of 

 their position according to the distinctions of the two groups 

 given by Rev. M. J. Berkeley (i), who says that "Fungi are 

 distinguished from Algae by deriving their nutriment from 

 the substance on which they live, and not from the sur- 

 rounding air or water-like Algae ; " also by Julius Sachs 

 (7) who states that "All Algae contain chlorophyll, and 

 have therefore the power of assimilation ; all Fungi are 

 destitute of chlorophyll, and are therefore parasites, or 

 live on organized products of decomposition." Specimens 

 of Menobranchiis lanceolatus, kept in a tank at the University, 

 became attacked by Saprolegna, which caused death ; and while 

 the animal was yet alive, by taking hold of the filaments of the 

 plant, the skin, when infested, could be readily lifted, thus 

 showing an inflamed portion beneath. Also, plants removed at 

 different times from the matrix on which they grew showed 



1 The greater part of the material in this paper on the genera, Saprolegnia and Achlya is 

 taken from my thesis for the degree B. S. 



2A list of works referred to is given at the end of the paper. The first figure designates the 

 number of the list. The last the page. 



