ON THE PROTECTION OF BUDS 67 



set betwixt the Leaves, from the Circumference to the 

 Center of the Bud; as in the Hasel.' 



Here he uses the term ' Surfoyls ' for the outer 

 scales, whatever their true character may be. His 

 ' Interfoyls ' are stipules. 



Besides the protection afforded by actual coverings, 

 the opening buds in many cases guard themselves, to 

 some extent, at any rate, by assuming either an erect 

 position, as in the Whitebeam (Pyrus Aria) (PL II. 

 fig. 5), Acer platanoides (PL II. figs. 2-4), and, I be- 

 lieve, most shrubs with opposite leaves ; or a drooping 

 attitude, as in the Lime (Tilia) (PL I. figs. 1-3), 

 Beech (Fagus) (PL IV.), Hazel Nut (Corylus), Elm 

 (Ulmus) (PL III.), &c. The great leaves of Palms are 

 at first vertical. 



One advantage thus gained is that the radiation 

 is much less than it would be if the leaves were to 

 assume at once their permanent horizontal position. 

 Darwin has shown that this position really does tend 

 to check the effect of radiation. Our experiments, he 

 says, ' show that leaves compelled to remain horizontal 

 at night suffered much more injury from frost than 

 those which were allowed to assume their normal vertical 

 position.' } 



1 We exposed on two occasions during the summer 

 to a clear sky several pinned-open leaflets of Trifolium 

 , which naturally rise at night, and of Oxrdis 

 1 Movements of Plants, p. 286. 



F2 



