^ ON THE MECHANISM OF LEAVES. 



placed so much in the manner of the fir leaves, that I was 

 ' deceived by it. But in the firs the rind and bark are all 

 leaves only, whereas in the ericse the leaves are wholly 

 detached, nor are they quite setssile, as may be seen at 

 fig. 5, dd. I shall now show the manner in which almost 

 all leaves that are evergreen, and have a shining surface, 

 are formed in their peduncle, having but ope gatherer, 

 which embraces the whole length of the leaf stalk. The 

 upper part alone puckers, as the motion requires only this 

 part to be gathered up, when the leaf is to be raised close to 

 the stem ; or stretched out, when it is to fall back : See 

 fig. 7, where e is the back and / is the front. 

 Beauty of the I have already said, that almost all leaves of trees have 

 leat bud when ^^^^^ qj ^^^ gatherers ; if only one, it is that adjoining tht 

 aein. stertty as it is that in which the buds of both sorts are con- 



tained ; nothing is more easy than to know the leaf from 

 the flower bud, even before they leave the stalk ; the leaf 

 bud is 80 peculiar in its appearance, it is impossible to mis- 

 take it ; it is composed of a quantity of hairs, or vessels, 

 which are already beginning to weave the leaf. It is more 

 than four times the size of the flower bud, and in trees 

 generally of a bright brown colour, very shining and beauti- 

 ful. See fig. 6, g g. I hardly know a subject more worth 

 studying in the solar microscope than ihisy if taken progres- 

 sively from its first beginning to its leaving the stalk as a 

 bud, for it is in this early state it shows the whole process of 

 weaving the leaf, as it protrudes not from the stalk till the 

 form is complete. Though Linneus admired much the 

 manner of pressing and folding the leaf, he was totally igno- 

 rant of its beautiful commencement. I have gi?en the 

 lower gatherer of the tilia, fig. 6. It is very curious to see, 

 when the flower buds are many in number, (fig. 6, h h,) how 

 the wood vessels and spiral wire will meander round them, 

 that they may not injure by passing over them ; for if, while 

 resting on the buds, they were suddenly contracted, they 

 would probably divide, and thus destroy them. I think I 

 have now shown the mechanism of most leaves, my next 

 letter will give the mechanical management of fioweTs, 

 I am, Sir, your obliged servant, 



AGNES IBBETSON. 



