INTRODUCTION 9 



or pubescens (a deciduous oak closely allied to our English oaks, 

 but with the leaves and young shoots thickly covered with felted hairs), 

 occurs here and there on the coast itself, but inland it increases in 

 importance and begins to form pure woods, while the Aleppo pine 

 diminishes in numbers. The hop- hornbeam (Ostrya carpinifolia), too, 

 a tree whose leaves and male catkins are almost indistinguishable from 

 those of the central and west European hornbeam (Carpinus Betulus) 

 but whose female catkins closely resemble hops, appears in considerable 

 numbers on sheltered northern slopes, from which the Aleppo pine 

 is practically absent. The undergrowth of these woods still consists 

 of typical Mediterranean shrubs, and on slopes with a southern ex- 

 posure Aleppo pine-woods still occur. This can be well seen on the 

 line of the " Sud de la France " railway between Vence and Grasse. 

 Much of this country, however, has been completely denuded of forest. 

 Further inland still and at a higher altitude, the Mediterranean pines 

 disappear altogether, and on northern slopes the Scots pine (Pinus 

 sylvestris) and the beech (Fagus sylvatica) begin to appear, along 

 with many deciduous central and west- European shrubs such as 

 hazel, roses, hawthorn, blackthorn, and flowers like our northern 

 violets, cowslip, dog's mercury, and so on ; while the Mediterranean 

 plants have nearly disappeared. 



We are now in the " montane region " with its markedly cooler 

 and damper climate, where snow lies in winter for long periods so as 

 to interrupt the active life of the vegetation. Even at this distance 

 from the coast, however, directly we descend into a broad valley 

 running east and west, such as those of the Esteron or of the Var, we 

 find the typical Mediterranean vegetation occupying the side facing 

 south, where it is both sheltered and warmed, while the northern ex- 

 posure is covered with woods of the Scots pine, often mixed with 

 deciduous oak and beech. The conditions favouring the develop- 

 ment of the Aleppo pine and the Scots pine are mutually exclusive, 

 so that the two trees very rarely exist side by side. The appearance 

 of the one species is the signal, so to speak, for the disappearance of 

 the other. 



Further north and at higher altitudes still, as we approach closer 

 to the main range of the Maritime Alps, spruce and larch woods 

 appear on the northern faces of the hills and the Scots pine shifts 

 round to the southern faces, for instance in the neighbourhood of 

 St. Martin Vesubie, behind Nice. We are now in the region of the 

 " subalpine woods " extending up to the limit of trees, and above this 

 limit we come into the region of true Alpine vegetation, and eventu- 

 ally of glaciers and snow-fields. 



