VEGETABLES. 



13y tliefe arrangements, any evaporation, except from the 

 appropriate tubes, is, it is thought, prevented. On the 

 hiwer lurtace of them, the external coat is a thin tranfparent 

 membrane full of cavities ; and it is probably altogether by 

 this furface, it is faid, that moillure and the principles of 

 the atmofphere necelfary to vegetation are abforbed or 

 taken up. 



The leaves in the greater number of plants annually decay, 

 and are reproduced ; their decay takes place either at the 

 clofe of the fummer, as in very hot chraates, when they are 

 no longer fupplied with fap, on account of the drynefs of 

 the foil, and the evaporating powers of heat ; or in the 

 autumn, as in the northern climates at the commencement 

 of the frofts. In common cafes, the leaves preferve their 

 functions no longer than there is a circulation of fluids 

 through them. The colour alTumed in the decay of the 

 leaf, feems, it is faid, to depend upon the nature of the 

 chemical change ; and that as acids are generally developed, 

 it is ufually either reddifli-brown or yellow ; yet there are 

 great varieties. Thus, in the oak it is a bright-brown ; 

 in the beech, orange ; in the elm, yellow ; in the vine, red; 

 in the fycamore, dark-brown ; in the cornel-tree, purple ; 

 and in the woodbine, blue. The caufe of the prefervation of 

 the leaves of evergreens during the winter is not well known. 

 It is found that the force of the fap is much lefs in vege- 

 tables of this fort, and there is probably a certain degree 

 of circulation throughout the winter feafon ; their juices are 

 lefs watery than tliofe of other plants, and probably lefs 

 liable to be congealed by cold, and they are defended by 

 ftronger coatings from the attion of the elements. Tlie 

 produftion of the other parts of the plant may be noticed 

 to take place at the time the leaves are rnofl. vigoroufly per- 

 forming their funftions. If the leaves of a tree be ftripped 

 off from it in the fpring, it uniformly dies ; and when many 

 of thofe of foreil-trees are injured by blafts, the trees are 

 faid always to become ftag-headed and unhealthy in their 

 growth. 



The leaves, it is faid, are neceflary for the exiftence of 

 the individual tree ; the flowers, noticed below, for the con- 

 tinuance of the fpecies. 



In the flowers there are feveral different organs or parts, 

 the forms, vafcular nature, texture, and oi-ganization of 

 which ferve different important yfes and fundtions. That 

 which contains the rudiments of the feed has it never formed 

 as reproduftivo, without the aid of the influence of the 

 pollen, or fecundating duft provided for the purpofe. This 

 myfterious impregnation is, of courfe, neceffary to the con- 

 tinued fuccefiion of the different vegetable tribes. 



It has been noticed, that all the parts of a vegetable feem 

 to contribute to the formation of the flowers and fruits of 

 plants ; as, although the latter do not fwcU and ripen until 

 after the former have fallen, their rudiments or firft begin- 

 nings are in the flowers, of which they properly make a 

 part. Thefe lafl are confequently temporary parts of vege- 

 tables, allotted to the purpofes of generation, terminating, 

 as it were, the old vegetable?, and beginning the new ones. 

 Fruits confift; of nearly the fame parts as the ftems of vege- 

 tables, as a fort of fl^in or fine coat, which is a production 

 or continuation of that of the bark of an outer foft pulpy 

 (ubftance, and is the fame as that continued from the bark, 

 only that its veficles or cells are larger, and it is more fuc- 

 culent and juicy. There is commonly an inner pulp, which 

 is next to the core ; and the core itfelf is nothing more than 

 a hard woody covering, that includes the feed. It is to be 

 noticed, however, that the formation of the fruit is very 

 various : in fome cafes, the feeds are difperfed through the 

 pulpy fubftance ; in fome, inftead of a core, a ftrong woody 

 material is met with, inclofing the feed or kernel, which, 

 I 



from its great hardnefs, is termed a ftone ; in fome, there is 

 a number of feeds ; and in others, only a fingle feed, in- 

 clofed in a large mafs of pulpy matter. See Fruit. 



The feeds are the deciduous parts of vegetables, each 

 feed including the rudiment of a new plant, imbued with the 

 vital principle, which it is capable of retaining for a vafl 

 length of time. A feed confiils of difi^erent parts, as that 

 which is neceffary to the produftion of the new plant or 

 vegetable within the feed, termed the corcule ; which is 

 divided and diftinguifhed into the fcaly afcending part, 

 named the plumule, and the plain defcending part, called 

 the roftel ; with different others of lefs importance, fome of 

 which are perifliable. It has been commonly fuppofed, and 

 not without probability, that the perfeft plant, or the or- 

 ganization neceffary to it, exifls in the feed, furrounded by 

 a quantity of farinaceous matter, which ferves to abforb 

 moifture, and to furnifli nourifliment to the corcule, until 

 its parts are fufficiently unfolded to draw fupport from the 

 foil in which it is placed. This is finely illuftrated in the 

 dwarf kidney bean, which, when lleeped fome time in water, 

 and it begins to fwell, may be eafily feparated into its two 

 lobes, between which is feen the nafcent plant or vegetable. 

 The flem, and its conneftion with the lobes, too, are clearly 

 feen ; and numberlefs veffels ramify through the lobes, whicli 

 dircftly communicate with the embryo plant or vegetable. 

 And on the external furface of the feed are abforbent veffels, 

 that take up moiflure, by which a fort of fermentation is 

 produced, and a liquid material formed, elaborated and pre- 

 pared by a particular procefs, which is proper for the 

 nourifhment and fupport of the plant or vegetable, in its 

 firll tender growth. In this early growth, the lobes of the 

 feed, whicli are provided with a mealy material, are likewife 

 found neceffary. And the firft leaves, or thofe which are 

 called feminal, are thought to appear not lefs neceffary than 

 the lobes to the perfedtion of the plant or vegetable ; as, if 

 they happen to be broken off or deifroyed, the plant or 

 vegetable experiences a proportional lofs of ftrength and 

 vigour in its growth. 



There is, therefore, to be diftinguifhed in every feed an 

 organ of nourifliment, a nafcent plant, and a nafcent root. 

 The lirft of thefe, in wheat and many graffes, is a fingle 

 part ; in other inftances, it coofifts of more than two 

 parts ; but in the greater number, it is fimply divided into 

 two. 



The feed, which is the laft produftion of vigorous vege- 

 tation, is wonderfully diverfified in form. That being of 

 the higheft importance to the refources of nature, it is de- 

 fended above all other parts of the plant, it is faid, by foft 

 pulpy fubftances, in tlie efculent fruits ; by thick mem- 

 branes, in the leguminous vegetables ; and by hard fhclls, 

 or thick external coverirsgs, in the palms and graflies. 

 Though the matter of the feed, in its common ftate, may 

 appear wholly inert and inactive ; when afted upon by moif- 

 ture, heat, and air, it foon diftinftly developes itfelf, and 

 becomes a complete plant in root and ftem. 



The above obfervations have been chiefly taken from the 

 works of Hooper and Davy, to which the reader may be 

 referred. See Seed. 



As vegetables are fupplied with proper veflels, thofe of 

 the abforbent kind on the furfaces of them take up the nu- 

 tritious fluid or material, and convey it to the different 

 parts. The furface of a plant has two fets of abforbents, 

 as already feen, which conftitute the abforbent organ of 

 vegetables ; as the mouths of the veffels of the radicles of 

 the roots, and thofe on the furfaces of the leaves. The 

 root, as long as it remains foft and tender, imbibes and 

 takes up the nutritious juices from the earth, by means of 

 the abforbent mouths of its veffels ; but as foon as it be- 

 comes 



