8!) 



Conjugation in Spirogyra. 



By F. M. Andrews. 



A lar.ue (jiiiintit.v ci!' S|iii'ii,iiyni crassa and Spirogyra roiiHiiuiiis were 

 Inniid ill Seiiten!l)er in a pond and npim examining it botli forms were 

 funnd to Ije conjugating. Not only was the species Spirogyra crassa found 

 conjugating togetlier, but sometimes Spirogyra crassa was found conjugat- 

 ing witli Spirogyra communis. Tlie smaller one of tlie two filaments in 

 Fig. 1 is Spirogyra communis and tlie larger one Spirogyra crassa. The 

 contents of tlie majority of the cells pass from the larger species to the 

 smaller ones fornnng a zygosixtre. and in other cases the contents of most 

 of the cells of Spirogyra communis pass into the cells of Spirogyra crassa. 

 Some of tlie forms here shown which had not begun to conjugate began 

 and completed conjugaticvn when brought into the laboratory. In an 

 earlier paper I have called attention to the interesting facts tlie hybrid 

 forms may show.' 



Figure 1 . 



Generally it is the case that when Spirogyra Is conjugating the con- 

 tents of the cells of one Hlament will all pass over into the cells of the 

 other tilament near it, as text-books and authors state. This is by no 

 means always the case as is shown by Fig. 2.- In some cells, as will be 

 seen at A and B, Fig. 2, the contents of the contiguous cells in the same 

 filament go to corresponding contiguous cells in tlie other filament, but the 

 contents of other cells as C and D, Fig. 2, do not do so, but go in the 



1 Andrews, I-\ M. BuUetin of the Torvfy Botanical Cluli, Vol. :^8, p. 296. 

 ^ Bennett and Murray, p. 266. 



