318 



BEAUTIES OF BBITISH TBEES, 



[Maech, 



or copses. It may reach a height of twenty feet, hut seldom attains 

 any considerable girth, and is more often a mere bush from six to ten 

 feet high. The whole plant is remarkable for its smoothness, for 

 even when the young green wood becomes grey from the development 

 of cork beneath the epidermis, the bark remains even in surface. A 

 point of some physiological interest occurs in connection with this 

 formation of cork. A few woody plants, such as Mistletoe and the 

 Pennsylvanian j\Iaple (Acer ptnnsylvanicumi) , never form any cork at 

 all, but retain their epidermis and green colour : others, such as the 

 Willows and Fomacece (Apples, Pears, &c.), form cork from the 

 epidermis itself, and, like most trees, do so towards the end of the 

 first summer in the life of the shoot. In some few plants, such as 



FBUIT OF SPINDLE TEEE. 



the Clematis and the Vine, cork originates in the ' bast,' or inner 

 layer of the bark, and as a consequence the bark comes away in long 

 strips ; but in Euonyimis, whilst it arises, as in the majority of trees, 

 just below the epidermis, its formation takes place not on yearling 

 shoots but on those several years old, and until it is formed the branch 

 remains green externally. Anyone cutting a switch of Hazel, HoUy, 

 Privet, or, in fact, almost any wood, may notice the bright green layer 

 beneath the dull-coloured external cork. 



The four-sided shoots of the Spindle-tree put forth in April deKcate 

 smooth pairs of egg-shaped leaves of a rather deep shade of green, on short 

 stalks, each leaf being two or three inches long with a finely-toothed 

 margin and tapering to a point. Among these about a month later 



