Lily-kin and Rose-kin 135 
For there mild winters sometimes favor almost 
continuous growth, and cambium may be present, 
and new wood may be formed, during almost any 
month in the twelve. The rings of a tree (Fig. 
28) are a trustworthy guide only in northern lati- 
tudes, where vegetation has a period of vigorous 
growth followed by a period of torpor. 
In all dicotyledenous trunks the newest. wood 
Fic. 28.—Crosswise section of the trunk of a young oak-tree, 
showing growth-rings. 
(From the Vegetable World.) 
lies just beneath the inner bark, and the older 
wood toward the centre. So a little is added to 
the girth by each year’s growth, till the enor- 
mously thick trunks of some or our larger forest- 
trees are built. 
The differences between the rose’s kindred and 
the lily’s kindred culminate in their flowers. The 
