684 THE PLANE. 



renewed, by which it breathes freely even in the smoke-laden air ; of 

 the hollowed leaf-stalks where the buds lie hidden, and the frilled 

 cups which surround the young leaves. The beauties of the Londoner's 

 tree are, indeed, many enough to secure their gratitude and homage. 



SPECIES OF PLANES. 



Botanists observe two species, namely, the Western Plane (Platanus 

 Occidentalis) and the Oriental (Platanus Orientalis). The latter is said 

 to have more deeply indented leaves, to shed its bark in smaller 

 sections, and to possess smaller and rougher Iruits than the former. 

 Individual trees of the London Plane (Platanus Orientalis — variety 

 Acerifolia), however, bear both forms of leaves, some cut into three 

 simple lobes, others deeply cleft into three or five, and sub-divided 

 by numerous jagged incisions. The distinctions between the species do 

 not appear to be sufficiently well-marked to call for separate descrip- 

 tions. 



GENERAL REMARKS.— LEAF-BUDS. 



The ingenious manner in which young leaves in the bud are 

 packed together has already been referred to in this book. By one 

 common arrangement the folded leaves lie in opposite right-angled 

 pairs. That is to say, where the bud contains four pairs of leaves 

 their positions relatively to one another are those of the four points 

 of the compass : the first and third pair occupying the points north 

 and south, the second and fourth pair the points east and west. This 

 arrangement holds good in the case of the Horse-Chestnut, Ash, Maple, 

 Sycamore, Spindle, Guelder-Rose, and Buckthorn. 



In other cases the leaves are in opposite pairs, that is to say, 



