136 PROF. AILMAN ON THE 



features are scarcely again met with before arriving at the 

 latitude of Naples, about four degrees further south ; for through- 

 out Lombardy, Tuscany, and the districts formerly included in 

 the Pontifical States, the plants mainly belong to the forms of 

 Central Europe. It is to some of the characters of the flora of 

 Provence and Liguria that I now wish to call your attention., 



It is no part o£ my purpose to occupy you with the details of 

 Mediterranean botany. However limited may be the district 

 under review, such details would be unsuited to an occasion like 

 the present, even did the time at our disposal allow of our enter- 

 ing into them. I shall therefore confine myself to those general 

 aspects of the flora which exert an influence on the natural 

 scenery — to that special physiognomy of the vegetation by which 

 the traveller from the north becomes instantly impressed with 

 the conviction that he has entered on a distinct and unfamiliar 

 phase of organic nature. 



When we seek for the conditions which give to the flora of the 

 western Riviera a character so essentially its own, we find a 

 climate remarkable for the mildness of its winters and the high 

 temperature and dryness of its summers. It is thus neither a 

 purely insular nor a purely continental climate ; for the cool 

 summers of the former and the rigorous winters of the latter are 

 here equally absent. 



No less peculiar is the distribution of rain throughout the 

 year. The season of rains is confined to the winter and spring 

 months, while the summer is, as a rule, absolutely rainless. 



"With the most important elements of climate thus distributed, 

 a well-marked influence must be exerted in determining the 

 periods of active vegetation. After the winter rains have 

 supplied the humidity essential to the perfect development of 

 vegetation, there bursts upon the whole country with the coming 

 spring a richness of foliage and of blossom as beautiful in its forms 

 and in its colours as it is marvellous in its suddenness. And 

 then when spring is succeeded by the hot rainless summer, vege- 

 tation becomes arrested, and the freshness of the spring land- 

 scape is gone ; for even the evergreens become dull and lustreless 

 under the increasing heat and aridity of summer. 



If there be one feature more than another which characterizes 

 the vegetation of the Mediterranean shores it is the abundance 

 of evergreen trees, belonging to forms different from that of the 

 acicular-leaved Coniferae j and in no part of these shores is the 



