INTRODUCTION 3 



the carbonic acid of the air by the aid of light uninterruptedly 

 during the whole year. At the same time the very dry, hot summer 

 makes it necessary for the leaves to be protected from too great loss 

 of water by evaporation, and therefore they have a thicker watertight 

 covering than is usual in the leaves of the northern deciduous trees 

 and shrubs. In many cases, too, they are covered either on the 

 lower or on both surfaces by a thick felting of hairs. Also the leaves 

 are thicker and their texture is generally much closer another means 

 of checking loss of water by evaporation so that they are less trans- 

 lucent and of a dark, duller green than is the case with our native 

 trees and shrubs. Finally, the leaves of the Mediterranean woody 

 plants are on the whole much smaller and frequently narrower than 

 is the case with more northern types. 



All these points can be readily verified in five minutes' examina- 

 tion of the trees and shrubs of the woods or scrub on any of the 

 rocky hillsides of the Riviera. Compare for instance the leaves of 

 the evergreen oaks with those of our own oak or beech, or the leaves 

 of any of the shrubs with those of the English hazel, and the differ- 

 ence can be seen at once. It is probable that the leaf of a typical 

 Mediterranean shrub is able to do much less work for the plant than 

 that of a typical English shrub during the same period, but this is 

 compensated for by the fact that it is able to work during the whole 

 year instead of being limited to a life of about five months. 



Besides the ordinary flat kind of leaf, plants with long needle- 

 shaped leaves, i.e. with much reduced surface and therefore with even 

 more limited evaporation of water, are very common in the Mediter- 

 ranean region. Conspicuous among these are the pines, of which 

 most of the Mediterranean woods are mainly composed, the tree 

 heath, exceedingly common in many places, and such shrubs as the 

 rosemary. It is true that pines and heaths though not, in general, 

 the same species also grow in England, but only on special kinds 

 of soil, where they cannot obtain much water. Thus we see that the 

 Mediterranean trees and shrubs are quite distinctive and very well 

 adapted to the climate in which they live. 



There are three kinds of pine which grow wild on the Riviera 

 the maritime pine (Finns Pinaster or maritima), the Aleppo pine 

 (Pinus halepensis] and the stone pine (Pinus Pined). Each of these 

 is characteristic of a separate kind of situation or habitat, and forms 

 in its own habitat nearly pure woods, though mixtures of the species 

 do occur in certain places. 



WOODS OF MARITIME PINE AND CORK-OAK. 



The maritime pine is a tall, handsome tree with very long and stiff 

 sharp-pointed dark green needles. Sometimes these needles reach 

 a length of eight inches, but that is exceptional ; a length of five 

 inches is, however, quite common. The cones are also very large and 

 have a rich brown " lacquered " surface. 



