Trees on McGill University Grounds. 423 



species the only one to which I gave attention was the P. 

 grandidentata, the large-toothed aspen, because of its resem- 

 blance to some fossil species, and the wonderful variety in 

 form and texture of the leaves on shoots and branches of dif- 

 ferent ages, as illustrating the diversities of foliage in these 

 fossil species. The tree is, however, of straggling and irre- 

 gular habit of growth, and scarcely worthy of cultivation 

 except for its tremulous leaves, in which property it is sur- 

 passed by its ally, P. tremuloides, but this also is a straggling 

 and usually ungraceful tree. 



32. Willows. Salix. (Species.) 



Some plants of native willows existed originally in the 

 grounds, and seemed to have been less attractive to brows- 

 ing cattle than most other shrubs. The bright yellow cat- 

 kins of the male plants formed an attractive feature in early 

 spring. They appear, however, to be of short life and 

 require to be frequently renewed. In recent years some 

 foreign species of fine appearance were presented by Mr. 

 G-ibb. Two of these, more particularly, a gray or olive-leaved 

 species and one with shining dark green leaves, were espe- 

 cially attractive and proved hardy and rapid growers. 

 They are well deserving of attention where beautiful foli- 

 age is desired in a short time and where the soil is moist. 

 The same remark may be made as to some of the finer 

 varieties of the white-leaved poplar. The beautiful golden 

 willow was early planted along the side of the brook, and 

 though for some years it was impossible to protect the 

 plants from the knives of schoolboys, they eventually over- 

 topped their assailants and grew to the stature of trees, 

 which formed a very pleasing variety in contrast with the 

 maples and spruces. 



33. Wild Cherry and Plum. Prunus. (Species.) 



The choke cherry (Prunus virginiand), the black cherry 

 (Prunus serotina), the common wild red cherry (Prunus 

 pennsylvanica), and the wild plum (Prunus americana), 



