206 



degree than of any other species of Spirogyra that was tested. Since 

 the phenomenon was observed once in a physiological condition that had 

 been made favorable for conjugation and again where conjugation was 

 actually taking place, it was at first thought that the branches were exag- 

 gerated attempts at conjugation, and. in some instances, this may have 

 been the case. But the filaments were usually close enough together that 

 such long tubes would not have been necessary, and no actual union of 

 gametes as a result of any such activity was at any time observed. 

 Moreover, the filaments shown in Fig. 4 illustrate a condition noted in two 

 or three cases, where filaments having mature zygotes in some of their cells 

 were attached by these branches to others also containing zygotes. The 

 filament shown in this figure as holding to another by means of the foot- 

 like branch was a long one and had at another place mature zygotes that 

 had been formed as a result of conjugation with some other filament. If 

 these branches were modified conjugating tubes, a relation of this sort 

 would be out of harmony with the tendency toward bisexuality that is 

 usually exhibited by the plant. 

 Indiana University, 



Bloomington, Indiana. 



Literature Cited: 



(1) Wolle, Rev. Francis. Fresh water alga? of the United States. 1887. 



(2) Collins, Frank S. Green algae of North America. 

 Tufts College Studies, Vol. II, No. 3. 1909. 



(3) Wood, Horatio C. Jr. A contribution to the history of the fresh water algae of North 



America. 

 Smithsonian Contributions, No. 241, Vol. 19. 1S72. 



(4) Pickett, F. L. A case of changed polarity in Spirogyra elongata. 

 Bui. Tor. Bot. Club, Vol. 39. 1912. 



(5) Weatherwax, Paul. Aphanomyces phycophilus De Bary. 

 Proc. Ind. Acad, of Sc. 1913. 



