24 TERRESTRIAL ADAPTATIONS. 



present length. If the summer and the autumn 

 were much shorter, the fruit could not ripen ; if 

 these seasons were much longer, the tree would 

 put forth a fresh suit of blossoms, to be cut down 

 by the winter. Or if the year were twice its 

 present length, a second crop of fruit would 

 probably not be matured, for want, among other 

 things, of an intermediate season of rest and 

 consolidation, such as the winter is. Our forest 

 trees in like manner appear to need all the seasons 

 of our present year for their perfection ; the 

 spring, summer, and autumn, for the develope- 

 ment of their leaves and consequent formation of 

 their proper juice, and of wood from this ; and the 

 winter for the hardening and solidifying the 

 substance thus formed. 



Most plants, indeed, have some peculiar func- 

 tion adapted to each period of the year, that is 

 of the now existing year. The sap ascends with 

 extraordinary copiousness at two seasons, in the 

 spring and in the autumn, especially the former. 

 The opening of the leaves and the opening of the 

 flowers of the same plants are so constant to their 

 times, (their appointed times, as we are naturally 

 led to call them,) that such occurrences might be 

 taken as indications of the times of the year. It 

 has been proposed in this way to select a series 

 of botanical facts which should form a calendar ; 

 and this has been termed a calendar of Flora. 

 Thus, if we consider the time of putting forth 



