U OP BUDS. 



the oldest being in the centre of the trunk, and the newest forming 

 tlie outer layer. This kind of stem may be seen in the oak and other 

 forest trees in our climate, and also in most of our common herba- 

 ceous plants ; these spring from seeds with two cotyledons, and ar-e 

 called dicotyledonous. 



2d. Stems which grow internally, as palms and grasses : here the 

 wood, instead of circling around the first formed substance, is pushed 

 outwards by the development of new fibres in the centre ; this kind 

 of stem belongs to plants whose seeds have but one cotyledon, and 

 are therefore called monocotyledonous* 



LECTURE VIII, 



Most leaves and flowers proceed from scaly coverings called buds. 

 The scales envelop each other closely ; the exterior ones being dry 

 and hard, the interior moist, and covered with down ; they are also 

 furnished with a kind of resin or balsam, which prevents the embryo 

 from being injured by too much moisture. Buds have been known 

 to lie for years in water, without injury to the germ within. 



The sap is the gi'eat fountain of vegetable life ; by its agency new 

 buds are yearly formed to replace the leaves and flowers destroyed 

 by the severity of winter. Branches also originate from buds. Lin- 

 nasus supposed that buds spring from the pith, this being found ne- 

 cessary to their formation and growth. The bud is a protuberance 

 formed by the swelling of the germ ; and as, for this purpose, the 

 agency of an additional quantity of sap is needed, we see the bud 

 appearing at the axils of leaves, or the extremities of branches and 

 stems, where there is an accumulation of this fluid. If you plant a 

 slip of Geranium, you will observe that it either sprouts from the axil 

 of a leaf, or from knots in the stem, which answer the same purpose 

 as the leaf, by slightly interrupting the circulation of the juices, and 

 thus affording an accumulation of sap necessary for the production 

 of a new shoot. 



Some botanists distinguish the different periods of the bud as fol- 

 loAvs : first, the point in the plant which gives rise to the bud, is called 

 the eye ; when this begins to swell and become apparent, it is termed 

 the button; and when it begins to unfold, the bi(d.'\ 



Herbs and shrubs have buds, but these usually grow and unfold 

 themselves in the same season, and are destitute of scales ; while the 

 buds of trees are not perfected in less than two seasons, and, in some 

 cases, they require years for their full development. You have, no 

 doubt, observed in the spring, the rapid growth of the leaves and 

 branches of trees ; and perhaps, have also noticed, that as summer 

 advances, the progress of vegetation seems almost suspended. But 

 nature, instead of resting in her operations, is now busy in providing 

 for the next year ; she is turning the vital energies of the plants to 



* These two kinds of stem have by some French botanists been called exogenous 

 and endogenous : these words are derived from the Greek ; the first signifying to groto 

 externally, the second, to grow internally. 



+ These terms in French, are todil, the eye, bouton, the button, and bourgeons, th6 

 bud. 



Dicotyledonous stems— Monocotyledonous stems— Description of buds— Agency of 

 sap— Tlie eye, button, and bud— Herbs and shrubs destitute of scaly buds. 



