ENQUIRY INTO PLANTS, I. x. 1-2 



Differences in leaves. 



X. ^ Now, while the leaves of all other trees are 

 all alike in each tree, those of the abele ivy - and 

 of the plant called kroton (castor-oil plant) are 

 unhke one another and of different forms. Tlie 

 young leaves in these are round, the old ones 

 angular,^ and eventually all the leaves assume that 

 form. On the other hand* in the ivy, when it is 

 young, the leaves are somewhat angular, but when 

 it is older, they become rounder : for in this plant 

 too a^ change of form takes place. There is a 

 peculiarity special to the olive lime elm and abele : 

 their leaves appear to invert the upper surface after 

 tlie summer solstice, and by this men know that the 

 solstice is past. Now all leaves differ as to their 

 upper and under surfaces ; and in most trees the 

 upper surfaces are greener and smoother, as they 

 have the fibres and veins in the under surfaces, even 

 as the human hand has its ' lines,' ^ but even the upper 

 surface of the leaf of the olive is sometimes whiter 

 and less smooth.^ So all or most leaves display 

 their upper surfaces, and it is these surfaces which 

 are exposed to the light." Again most leaves turn 

 towards the sun ; wherefore also it is not easy to say 

 vhich surface is next to the twig^; for, while the 

 way in which the upper surface is presented seems 

 rather to make the under surface closer to it, yet 

 nature desires equally that the upper surface should 

 l:e the nearer, and this is specially seen in the 

 turning back ^ of the leaf towards the sun. One 



^ ivloTt /col ri vxria conj. W. ; Xela oe koX to tov Ktrrov 

 ilSS. A makeshift correction of an obscure passage. 

 ' c/. Plin. /.<-. ^ i.e. is the under one. 



® Whereby the under surface is exposetl to it : see above. 



69 



