66 



there is a decided difference in the staining reactions of the con- 

 jugating cells and those which are not conjugating. The con- 

 jugating cells are clearer, not taking the stain so readily. This 

 "clarification" seems general in the conjugating cells and may 

 possibly be connected with the fact that their cell walls are 

 thinner. The substances in suspension may have gone into 

 solution. In the conjugating cells also, the nuclei at first seem 

 to draw apart a little as if repelled. Sometimes two male cells 

 conjugate with one female cell. In general, previous to con- 

 jugation, the pyrenoids are much larger. 



A short discussion followed on the cause of conjugation, with 

 the conclusion that it was probably essentially chemotactic. 



An interesting specimen of a woody plant {Bachira alba) from 

 the island of St. Thomas was shown by Dr. Britton. The bark 

 was of a very corky nature and showed in places on the surface 

 a peculiar green color. 



Arthur H. Graves, 



Secretary. 



Meeting of April 8, 1924 



This meeting was held at the American Museum of Natural 

 History. Professor Richards occupied the chair. The Secretary 

 of the Club gave an illustrated talk on the Civic Value of 

 Trees, describing the life and growth of trees and the unfavor- 

 able conditions to which city trees are subjected, the diseases 

 to which they are liable and correct methods of planting and 

 treatment. The value of trees to a city was summed up as 

 follows: 



1. Beautify the city, making it a more desirable dwelling place. 



2. Source of interest and pleasure at all times of the year. 



3. Afford cooling shade throughout the hot summer period. 



4. Enhance the value of real estate. 



5. Improve the general morale of the community. 



Arthur H. Graves, 



Secretary. 



Meeting of April 30, 1924 



The meeting of this date was held in the Laboratory Building 

 of the Brooklyn Botanic Garden. 



