BOTANY.
According to the Linnsean system, plants take their denominations from the sex of their flowers, in the following manner :-1. Hermaphrodite plants, are such as upon the same root bear flowers that are all hermaphrodite, as in most ge nera. 2. Androgynous, male and female, such as upon the same root bear both male and female flowers, as in the class Moncecia. 3. Male, such as upon the same root bear male flowers only, as in the class Dicecia. 4. Female, such as upon the same root bear female flowers only, as in the class Dicecia. 5. Polygamous, such as, either in the same individual plant, or in different individual plants of the same species, have hermaphrodite flowers, and flowers of either or both sexes, as in the class Polygamia. All plants, however minute, are propagated by seed ; and so easy is their cultivation, that in many instances they may be rear ed by parting their roots, or depositing layers, cuttings, &c. of the parent stock, in such soils as are most congenial to their nature. Hence some botanists con sider them as somewhat analogous to animals ; a conjecture that is strongly roborated by the regular circulation of the sap throughout all their parts; and by the sleep of plants, or the faculty which some possess of assuming at night a position different from that in which they appear during the day. In the second volume of the Manchester Transactions, we find some speculations on the perceptive power of vegetables, by Dr. Percival, who attempts to show, by the several ana logies of organization, life, instinct, spon taneity, and self-motion, that plants, like animals, are endued both with the powers . of perception and enjoyment. The at tempt, though ingeniously supported, however, fails to convince. That there is an analogy between animals and vege tables is certain ; but we cannot from thence conclude, that they either per ceive or enjoy. Botanists have, it is true, derived from anatomy and physiology al most all the terms emplo) ed in the de scription of plants. But we cannot from thence conclude, that their organization, though it bears an analogy to that of ani mals, is the sign of a living principle, if to this principle we annex the idea of perception. Yet so fully is our author convinced of the truth of it, that he does not think it extravagant to suppose, that, in some future period, perception may be discovered to extend even beyond the limits now assigned to vegetable life.
Mr. Good, the learned author of the translation of Lucretius, delivered in the spring of the present year, before the Medical Society of London, a discourse " On the general Structure and Physio logy of Plants compared with those of Animals, and the mutual Convertibility of their Organic Elements," which con tained much interesting matter, and many curious and ingenious speculations. He
began by assuming, what indeed is the basis of the sexti'M system, that every thing that has life is produced from an egg ; that the egg of the plant is its seed. The seed is sometimes naked, and some times covered with a pericarp, which is of various forms and structures : the seed itself consists internally of a corculum, or little heart, and externally of a paren chymatous substance, called a cotyledon, which is necessary for the germination and future growth of the seed, and may he denominated its lungs or placentule. The corculum is the " punctum saliens" of vegetable life, and to this the cotyledrn is subservient. The corcle consists of an ascending and descending part : the for mer is called its plum le, which gives birth to the trunk and branches; from the latter spring the root and radicles. The position of the corcle in the seed, which is always in the vicinity of the eye, is a cicatrix, or umbilicus, remaining af ter the separation of the fimis from the pericarp, to which the seed has been at tached. The first radicle elongates, and pushes into the earth, before the plumule evinces any change : like the cotyledon, the radicles consist chiefly of lymphatics and air-vessels, which serve to separate the water from the soil, in order that the oxygen may be separated from the wa ter. Hence originates the root, the most important part of the plant. The solid parts of the trunk of the plant are the cortex, or outer bark ; the liber, or inner bark ; the alburnum, or soft wood ; lig num, or hard wood ; and medulla, or pith. These lie in concentric circles ; and the trunk enlarges, by the formation of a new liber, or inner bark, every year ; the whole of the liber, excepting indeed its outermost layer, which is transfbrmed into cortex, becoming the alburnum of the next, and the alburnum becoming the lignum. Hence a mark of any sort, as the initials of a name, which has pene trated through the outer into the inner bark, must in a long process of years be transferred to the central parts of the trunk. Independently of these more so lid parts of the trunk, we generally meet with some portion of parenchyma and cellular substance : the vessels contained in this may be compared to arteries and veins, air vessels, and lymphatics. The lymphatics lie immediately under the cu ticle, and in the cuticle, and by branching different ways are enabled to perform the alternating economy of inhalation and exhalation : below these lie the arteries, which rise immediately from the root, and communicate nutriment in a perpen dicular direction : interior to these lie the reducent vessels, or veins, which are softer and more numerous, and in young shoots run down through the cellular texture and the pith. Between the ar teries and veins are situated the air vessels.