58 The Ottawa Naturalist. [June 



BOTANY. 



Meetings of the Botanical Branch. 



The sixth meeting: was held at the residence of Mr. D. A. 

 Campbell, on the evening- of May 15th. He exhibited a large 

 number of mounted specimens oi plants with the object of illus- 

 trating- how leaves seem to vary according to their environment. 

 He held that where light is intercepted by water or by the crowd- 

 ing of plants, there is a tendency for leaves to subdivide. Prof. 

 Macoun was inclined to hold that leaf-division indicated relation- 

 ship rather than the effect of environment. In support of this, he 

 mentioned the fact that the first leaves of the Horse Radish are 

 much dissected, even in the driest soil. In the course of the dis- 

 cussion, this principle was enunciated : Generalize from not ^0 

 facts. 



As an aid to those who wish to become acquainted with the 

 different species of violets, the information was given by Dr. 

 Fletcher that at the Experimental Farm he had now growing all 

 the recognized species of this locality, as well as some which had 

 not been described. In addition, fine clumps could be seen of 

 several other species from different parts of Canada and the 

 United States. In all he had about 30 named species, many of 

 these at the present time in full flower. 



As far as known, all our wild plums are Pninus nigra and not 

 P. Americana as was once supposed. The points of difference 

 between the two species may be indicated in tabular form. 



Prtitnis nigra. Pniniis Aiiifi icaiia. 



I Sepals serrate or serrulate. Sepals entire. 



2. Petals white, becoming- pink. Petals white, not becoming pink. 



3 Leaves crenulale-serrate. Leaves sharply toothed. 



4. Fruit with no bloom. Fruit with a white bloom. 



Prof. Macoun mentioned that he had found the Shell-bark 

 Hickory at Pointe du Chene, the locality recorded in the " Flora 

 Ottawaensis " many years ago. Dr. Fletcher stated that it grew 

 not only there but also in greater abundance at Casselman, Ont., 

 30 miles from Ottawa. 



Dr. Fletcher, who had just returned from a trip to Hamilton, 

 showed some remarkable sports of Trillium grandifloriiin which, 



