2 88 



Canadian Record of Science. 



Fig. 5. Lonicera tartarica. Leaves from the plagiotropic branches of 

 a pruned shrub, somewhat reduced through correlation, x \ 



Apart from the general fact that the growth of all shrubs 

 during the past summer, was characterized by a more than 

 ordinary luxuriance, there appears to be no obvious reason 

 for the phenomenal growth of Lonicera, which requires some 

 special explanation. 



In addition to the tartarian honeysuckle, attention has 

 been drawn to three other instances which serve to emphasize 

 the point at issue. Clumps of Spiraea van houttei were 

 planted at the same time as the Lonicera, and they have been 

 subjected to the same course of treatment, being top pruned 

 in the spring of 1903. The variation of leaves in this plant is 

 a matter of familiar knowledge, but it offers collateral evidence 

 of much value, as illustrating the conditions under which such 

 variation arises. The strongly defined leaf variation of this 

 plant not only constitutes a conspicuous feature of its growth, 



