277 



NOTE ON CERTAIN VARIATIONS OF THE SPOROCYST IN A 

 SPECIES OF SAPROLEGNIA.* 



By Marjoeie 1. Collins, B.Sc, Linneax Macleay Fellow of the Society m 



Botany. 



(Witli eleven Text-figures.) 



Introduction. 



During the summer of 1919, a quantity of Saprolegnia Avas made available to 

 the writer by the aecidental drowning of a beetle, in a tank situated in the glass- 

 house of the Botany Department, University of Adelaide. The material, with a 

 little water from the tank, was transferred to the laboratory and kept under 

 observation for some weeks. It was found to show variations in sporocyst forma- 

 tion similar to these recorded by Lechmeref for Saprolegnia Thureti and certain 

 additional variations which are thought to be of sufficient interest to place on 

 record. 



Since sexual reproduction was not observed, it was impossible to identify the 

 species under examination with any accuracy. Judging by the stout nature of 

 the hyphae, however, it seems probable that the species is identical with that 

 of Lechmere's work. Saprolegnia Thur.-ti. 



The writer's thanks are due to Professor T. G. B. Osborn. University of 

 Adelaide, in whose Department these observations were made, for his interest in 

 the work. 



Previous In restigations. 



In his investigation of certain species of Saprolegnia Lechmeret draws atten- 

 tion to the marked variability in the nature of sporocyst formation and dis- 

 charge. In addition to the normal Saprolegnia type of sporocyst, he records five 

 variations, each of which shows features which are characteristic of a distinct 

 genus of the Saprolegniaceae. These variations are all concerned with the nature 

 of discharge of the sporoeysts, and sometimes result in the suppression of the 

 first, second or of toth motile phases. The following is a brief summary of the 

 sporocyst variations observed by Lechmere : — 



1. Leptolegnia condition, where the zoospores are arranged in a single row 

 in a long cylindrical sporocyst. Two motile phases. 



2. Pythiopsis condition, where the spores swarm feebly from a club-shaped 

 sporocyst, and come to rest near the mouth of the sporocyst. No record of a 

 second motile phase. 



*The observations recorded in this paper were made while the writer held the position 

 of Demonstrator in Botany, The University of Adelaide. 

 tNew Phytologist, ix., 1910, p.-TOS. 

 ILoc. lit. 



