THE PEAR HARVEST. 213 



toothed leaflets, arranged opposite one another on either 

 side of a common leaf-stalk, the wild service-tree has 

 broad leaves, vandyked only half-way through into a 

 few pointed lobes : and this type marks it out at once 

 as an intermediate stage between the very much divided 

 foliage of the true roses and the perfectly simple ellip- 

 tical foliage of the pear and the apple. 



From such a central junction, then, or rather from 

 some ancestral form closely resembling it, the primitive 

 pear-like bushes began once more to split up under 

 pressure of special selection into two divergent branches. 

 One branch, clinging rather to the mountainous 

 districts, and accommodating itself to the peculiar 

 circumstances of its own chosen habitat, developed 

 gradually into the rowan or mountain ash ; a moderate- 

 sized tree in sheltered uplands, a stunted shrub .on wind- 

 swept summits or at very high latitudes beside the 

 Arctic Circle. Like most other trees of windy regions, 

 it has its leaves divided into small opposite leaflets, to 

 prevent them from being tattered by the storms ; so 

 that here the vandyked lobes of the wild service-tree 

 have separated into a number of totally distinct pieces, 

 arranged in regular rows along a central leaf-stalk. 

 Indeed, it is a general principle of foliage that wherever 

 means of growth fail, the leaves become first indented 

 between the main ribs and finally separated into distinct 

 segments : which produces the immense variety in the 

 outer shape of closely related leaves, whose ribs and 

 veins nevertheless remain essentially identical. At the 

 same time, the berries of the mountain ash have grown 

 very numerous and bright red in hue, so as to attract 

 the arctic or northern birds, which have a keen eye for 



