Chapter II 

 FERTILIZATION (continued.) 



2. The Conjugation of the Zygosporcae 



The behavior of the chlorophyll-band of Spirogyra 

 during conjugation is very instructive. De Bary* has 

 already observed that in many species having one spiral 

 the two chlorophyll-bands of the conjugating cells join 

 their ends in such a way that they form a continuous 

 ribbon. For the one-spiraled species, 5". Weheri, how- 

 ever, Overton has quite recently described and figured 

 how the band of the maternal cell splits in the middle 

 during conjugation, and how the paternal band then in- 

 serts itself between the two halves and attaches itself to 

 their ends.^ Later, owing to the considerable swelling 

 of the pyrenoids, as well as to other processes, the 

 windings of the band gradually become more indistinct, 

 and finally, in the zygospore, quite indistinguishable, un- 

 til they reappear again during its germination.^ 



These data are quite sufficient to give us an idea of the 

 derivation of the chlorophyll-bands of the young germ- 

 plant. We assume, as a result of the above mentioned 

 investigations, that the chlorophyll-band of the germi- 

 nating zygospore consists of the bands of the two sexual 

 cells which are joined by their ends in one way or an- 



*De Bary. Die Conjugafen. p. 3. 



^Overton, C E. Ber. Dent. Bot. 5: 70. Taf. IV. 1888. 



^See also on this subject Klebahn. Ber. Dent. Bot. Ges. 6: 163. 

 1888. 



