of the Climate of Naples upon the Periods of Vegetation. 109 



Cherries* do not ripen at Paris before the latter part of 

 June, whilst at Naples they are eaten from the first week in 

 May. 



These facts always confirm the difference of the relations 

 between the periods of vegetation in those parts of the world. 



V. Defoliation, 



When the trees begin to be stripped of their leaves, vege- 

 tation finds itself arrived at that its last and mournful period, 

 which botanists call defoliation {defoliatio) . 



This phenomenon, in trees which annually lose the whole 

 of their leaves, takes place in the beginning of the autumn. In 

 evergreen trees the leaves prolong their vegetation beyond the 

 first year, and die after the new ones have already expanded 

 themselves. Although botanists have not paid great attention 

 to the fall of the leaf in evergreen trees, this phenomenon, 

 however, it may be shown, does not happen in periods less 

 constant than those which are observed in trees with annual 

 leaves, concerning which 1 will limit myself to relate some 

 few comparative notices. 



The fall of the deciduous leaves being produced by the tor- 

 pidness which acts on the motion of the vegetable juices, in 

 consequence of the diminution in the temperature that is 

 felt in the autumnal months, must necessarily be early in cold 

 countries and late in warm climates ; and, indeed, similar va- 

 riations in the years and weather exercise upon defoliation a 

 similar influence to that which we have seen to prevail in the 

 other times of vegetation. 



Hence it is that at Upsal, the Hazel, the Ash, the Lime, 

 the Maple, and the Poplar cast their leaves at the first sign 

 of autumn ; at Paris these same trees lose them in October, 

 whilst at Naples they keep in full leaf through the whole 

 month of November. The Apple, the Fig, the Elm, the 

 Birch, and the different kinds of Oaks, which at Paris are 

 deprived of their leaves in the beginning of November, near 

 Naples often retain them throughout December. Since, how- 

 ever, the coldness of autumn sometimes takes place very early, 

 as it did in the years 1807 and 1812, the fall of the leaf itself 

 is likewise premature. 



[Whitef observes, on the order in which trees lose their 

 leaves in England, — "One of the first trees that becomes naked 

 is the Walnut: the Mulberry, the Ash, especially if it bears 

 many keys, and the Horse Chestnut come next. All lopped 

 trees, while their heads are young, carry their leaves a long 



* According to White, near Sclbornc Wild Cherries are ripe July 22. 

 f Works in Natural History, vol. ii. p. 245. 



