Trees on McGiil University Grounds. 413 



11. The Arctic Birch. Betula pumila. 



A plant of this species presented by Mr. Gribb was tended 

 for several years on the terrace in front of the College, but 

 did not thrive and eventually died. I planted it alongside 

 of a Tamarisk in hopes of reconciling to the same conditions 

 these two trees of so different habitat. But the birch 

 drooped in the heat of summer and the branches of the 

 tamarisk were winter-killed, so the experiment was not 

 successful. The tamarisk survives as a small shrub, send- 

 ing up shoots from the root. The dwarf birch is dead. 



12. The Alder. Alnus incana. 



This common shrub grew plentifully on the borders of 

 the brook, forming a dense thicket on the flat ground near 

 University street, under which wei'e many shade-loving 

 ferns and herbaceous woodland plants. It is now extinct. 

 I may mention with it the English Alder — A. glutinosa — a 

 much finer plant, attaining to the dimensions of a small 

 tree on one stem. Specimens of this were given to me by 

 Mr. Young and grew vigorously for a few years, but seemed 

 liable to have the young wood nipped by frost in winter, 

 and finally perished. The cut-leaved variety seems more 

 successful ; and one specimen, presented by Mr. G-ibb, still 

 remains. 



13. The Basswood. Tilia americana, L. 



This tree is common on the mountain, but did not exist 

 on the grounds till planted. It is a rapidly growing and 

 beautiful tree, forming a fine variety with maples and elms, 

 and interesting in spring from its clusters of fragrant 

 flowers on a leafy peduncle, while its large heart-shaped 

 leaves afford a grateful shade. It does not appear to be a 

 tree of long life, and when pruned or wounded is very apt 

 to decay in the stem. A large specimen in the avenue, 

 which will have to be removed for the approach to the 

 engineering building, has suffered in this way, and though 



