

io BOTANICAL GAZETTE [tanuary 



Wesleyan University; S. G. Winter, Illinois Wqsleyan University; 

 and W. A. Matheny, Sardis, Ohio." 



Review of literature 



In 1803 Vaucher (6) tells of his attempt to work out the life- 

 history of the Conjugatae. For this purpose the genus Spirogyra 



Mulleb 



Conf 



made 



in the spring and it was found that this species would fruit and dis- 

 appear as early as February 15 and as late as March 20. The zygo- 

 spores which he had collected germinated July 15, and all seemed to 

 germinate on the same day. 



A history of the British freshwater algae by Hassall (3) appeared 

 in 1857. This well-known work contains descriptions of 42 species 

 of Spirogyra under the name Zygnema. A single hint is given as to 

 the time of year when conjugation takes place; namely, "The 

 species of this group of confervae may be found in a state of conjuga- 

 tion during the entire spring, summer, and autumnal months, but 

 more abundant in the spring." 



In 1874 The freshwater algae of the United States by Wood (9) 

 was published in the Smithsonian Report. Speaking of the Zygne- 

 maceae he says: "The family under consideration is among the 

 commonest and most widely diffused of all the freshwater algae. 

 They may be found in greater or less abundance at all seasons, but 

 the spores appear to be formed only in the spring and early summer, 

 at least these are the only times at which I have found fertile filaments. 

 In the neighborhood of Philadelphia I have collected them in excel- 

 lent condition as early as the beginning of April and as late as the 

 latter part of June. Further south conjugation of course commences 

 earlier, and fine specimens received by myself from Mr. Canby 

 were collected by him in Florida in February." 



The work of Paul Petit (5) entitled Spirogyra ties environs de 

 Paris appeared in 1880. No general statement is made regarding 

 the fruiting season of this genus, but, with one exception, dates are 

 given with the description of the different species. These dates show 

 that 20 of the 36 species described matured during March, April, and 



May; 



July. These were found 



