294 Count Gaston de Saporta on the Part played 



European plants ; the poplars, willows, alders, and maples 

 beliave just as they do in Europe; and the contrast between the 

 verdure and the flowers of the indigenous or tropical plants and 

 the naked aspect of the European trees is not one of the least 

 astonishing spectacles presented by the flora of this island. "We 

 may say, with justice, that the cold which, in northern countries, 

 hastens the fall of the leaf, instead of being the true cause of 

 this phenomenon, rather disturbs it in its regular course by 

 accelerating it and rendering it sudden ; whilst in temperate 

 climates (and even in the south of France), where, in consequence 

 of an almost insensible diminution of temperature, the physio- 

 logical action is the only one manifested, the denudation of the 

 trees with deciduous leaves takes place with a regularity which 

 clearly shows the real tendencies of each species— so that, instead 

 of assisting in that shower of leaves which denudes the branches 

 in so short a time in central and noi'thern Europe, each species 

 parts with its leaves in its turn with more or less rapidity, in 

 obedience to aptitudes equally diverse with the specific difier- 

 ences themselves. 



Thus, the absence of thermometric cold, far from depriving 

 plants with deciduous leaves of their true character, really re- 

 stores it to them. It leads us to recognize in them what they 

 really are — namely, trees whose leaves, being limited to a dura- 

 tion of a few months, tend to separate from the branch as soon 

 as the latter possesses formed buds, organs into which the sap 

 flows, abandoning the leaves to elaborate the rudiments of new 

 organs destined to become developed after an interruption of 

 variable length according to the species. 



In fact, the fall of the leaves in plants in which they are 

 deciduous is not always the sign of a complete sleep, but rather 

 the occasion of an intermittence of vegetation ; and for many 

 genera, such as Alnus, Betula, Conjlus, Ulmus, Populus, &c., of 

 which we have to note the characteristic presence during the 

 Tertiary epoch, this state is only, so to speak, the signal of the 

 floral evolution which is accomplished in the absence of the 

 leaves. The cold of our countries only opposes, retards, or even 

 interrupts the flowering of those trees which, when transported 

 into a milder climate, expand their flowers towards the end, or 

 even in the depth, of winter. Here, again, the thermometric 

 cold, far from coinciding with the pheuomenon, arrests or con- 

 fuses its phases by its occurrence, and especially by its irregular 

 return. 



The plants of which we are speaking are in reality in the same 

 circumstances as many tropical organisms the flowering of which 

 constantly takes place in the absence of the leaves, one por- 

 tion of the year being devoted exclusively to the evolution of 



