igi2] 



BRIEFER ARTICLES 



165 



there is an alternation of generations in at least Polysiphonia violacea, 

 and to offer at least some foundation for the belief that it is general 

 among the red algae. 



In 191 1 Professor T. C. Frye found in Polysiphonia material, col- 

 lected at the Puget Sound Marine Station in 1910, some specimens 

 showing both carpospores and tetra- 

 spores on the same individual. This 

 observation was made in the course 

 of laboratory work with a class and 

 no material was kept. He suggested 

 to the senior author of this note 

 that the subject be investigated 

 further at the Puget Sound Marine 

 Station. The junior author ex- 

 amined the Polysiphonia material 

 that was brought into the labora- 

 tory at the station during the ses- 

 sion of 191 1. In one lot of material 

 she found the same condition to 

 which Professor Frye had referred. 

 The material was collected in the 

 lower littoral zone on the rocky shore 

 of Turn Island, near Friday Harbor, 

 Washington. It has been identified 



W. A. Setchell 



Fig. i.— Camera lucida drawing of 



University of California as Pterosi- a portion of a ^/^/M^naC?) show- 



7 . mg on the same individual both 



phonia bipinnata and by Dr. Shigeo tetraS p 0res an d a cystocarp with a 

 Yamanouchi of the University of carpospore. 



Chicago as Polysiphonia sp. 



The fact that the mother cells had gone to the point of complete 

 division into tetraspores in the material examined indicates that the 

 tetraspores were not abortive, and the fact that carpospores were seen 

 issuing from cystocarpic plants that bore also perfect tetraspores indi- 



were not abortive. We have thus an indi- 



cystocarps 



vidual that is both sexual and asexual, which is inconsistent with there 



species 



asexual. 



Professor T. C. Frye and the senior author of this note are now at 

 work on the cytology of specimens of this species with a view to determin- 

 ing the sporophytic or gametophytic nature of this generation by means 

 of mitotic studies.— George B. Rigg and Annie D. Dalgity. 



