CHAPTER V. 



ACTION OP LEAVES. 



THEIR NATTTEE, STKrCTTTEE, TEIlirS, EPIBEEMIS, STOMATES. — ^EEEECI OP 

 LIGHT. — ^DIGBSTIOIT OE DECOMPOSITION OE CAEBONIC ACID. — ^INSENSIBLE 



PEE8PIEATI0N. — EOEMATION OP SECEEIIONS. FAIL OF THE LEAF. — 



FOEMATION OE BTTDS BY LEATES. 



A LEAF is an appendage of the stem of a plant, having one 

 or more leaf-buds in its axil. In those cases where no buds 

 are visible in the axil, they are, nevertheless, present, although 

 latent, and may be brought into development by favourable 

 circumstances. As this is a universal property of leaves, to 

 which there is no known exception, it follows that all the 

 modifications of leaves, such as scales, hooks, tendrils, &c., and 

 even the floral organs, hereafter to be described, may have the 

 same property. 



Buds axe, liowever, formed with, difficulty by such, modified leaves as 

 brown scales or mere membranous expansions, even although the 

 latter are capable of assuming the usual condition of leaves when 

 anythiug occurs to increase their force of development. The more 

 green, the more succulent, the more perfectly organized a leaf is, the 

 greater is its power of forming axillary buds ; and vice versd. That 

 the power of forming buds reaUy exists among leaves even when most 

 unlike their usual state is proved by such examples as that at p. 90 of 

 this work, where they are appearing even from among oarpeUary leaves. 

 In the Author's JElements of Botany, p. 75, -a. case is figured of buds 

 from the axils of leaves in the state of petals, and he has now before him 

 an example of a Clematis Sieboldi, received from Mr. WUson, Gardener 

 to the Earl of Burlington, in which six buds are formed in the axils of 

 stamens. Such examples are, however, whoUy exceptional. 



All leaves arrive at their final condition through intermediate 

 states ; and if their growth is arrested by any cause, whether 



