189 



PROCEEDINGS OF THE CLUB 



Wednesday, October 28, 1903 



The club met at the New York Botanical Garden at 3:30 p. M.; 

 twenty-six persons present ; Dr. Britton in the chair. 



Mr. Kenneth K. Mackenzie, of East Orange, N. J., was elected 

 to membership. 



Dr. MacDougal called attention to the abnormal fall-bloom- 

 ing of certain plants. In one case mentioned the spring flower- 

 ing was retarded till fall, owing to the proximity of a mass of ice, 

 this being a case of retarded development. He exhibited also 

 plants with flowers now open that should not normally open till 

 next spring, this being accelerated development caused by the 

 prevailing climatic conditions. 



Dr. Britton exhibited two forms of the common marsh mallow, 

 one with pink flowers the other with white flowers with a crim- 

 son center. The first is the well-known Hibiscus Moscheutos L. 

 The second form is not uncommon in various localities, but has 

 been considered merely a color variation. Recently it has been 

 observed that the fruits of the two forms are very different, show- 

 ing that they should be considered distinct species. Drawings 

 of the fruits were exhibited. No name has as yet been proposed 

 for the white-flowered form. 



Dr. Burton E. Livingston spoke on " The Influence of Osmotic 

 Pressure on the Cell." One of the widely accepted theories of the 

 action of osmotic pressure is that it is comparable to gas pressure. 

 It can act, however, only in the presence of water. Soluble salts 

 tend to diffuse throughout a given volume of water just as gases 

 do in a confined space. In cellular tissue there is no break in 

 the water connection, since the cell-wall is permeable by water 

 and by the salts dissolved in it. The protoplasmic lining of the cell 

 is, however, only semi-permeable, since it allows the passage of 

 some substances while preventing that of others. When living 

 cells are transferred from a dilute medium to a denser one, the 

 tendency is for them to lose part of the water they contain. The 

 cell contents thus become more or less shrivelled ; conversely, 



