INTRODUCTION. 



and when: pla}iti>er4id' riot vegetate (or produce young plants.) 

 The fmnmmrf, ao 'you 'knew; is a planta dicecia, that is, one 

 of those in which the male and female parts of generation are 

 upon distinct plants, (some being males and others females.) 

 We having therefore no male plants, the flowers of our female 

 were never impregnated with the farina of the male. There 

 is a male plant of this kind in a garden at Leipsic, twenty 

 German miles from Berlin. We procured from thence, in 

 April 1749, a branch of male flowers, and suspended it over 

 our females, and the experiment succeeded so well, that our 

 palm-tree produced more than an hundred perfectly ripe 

 'fruit, from which we already have eleven young palm-trees. 

 This experiment was repeated last year, and our palm-tree 

 bore above two thousand ripe fruit." 



A plant, like an animal, is a very compound organized 

 living being, in which various operations, both chemical and 

 mechanical, are continually carrying on, from its .first produc- 

 tion to its final dissolution. It springs from a seed fertilized 

 by the pollen of its parent plant. It takes in foreign sub- 

 stances by its inhaling and absorbent vessels. It extracts 

 from, and assimilates to its own substance, those parts of them 

 that are nutritious, and throws off the rest. It secretes a 

 variety of fluids by the means of glands, and other unknown 

 organs. It gives that motion to the sap, upon which the 

 continuance of its life depends. 



Of the theory of vegetation, or growth, propagation, and 

 nutriment of vegetables, our knowledge is very slight and 

 superficial. On making a transverse section of a tree, i. e. 

 cutting it through horizontally, it appears to consist of three 

 parts : 



I. The BARK, which is also subdivided into two parts, L 

 The cuticle, or external covering, which consists of numerous 

 layers of circular fibres or threads, which are easily separated 

 from each oilier. 2. The true bark, which appears upon 

 removing th,e former, and is a collection of cellular or spongy 

 substances, containing two kinds of organs ; the vessels 

 peculiar to the plants, and the longitudinal fibres or perpen- 

 dicular threads. 



II. On removing the bark, the WOOD appears. It has 

 been discovered to contain the vasa propria, or proper vessels, 

 and longitudinal fibres, besides large vessels with spiral or 

 curved coats, running from one end of the tree to the other, 

 and are denominated vasa ueriu, or air-vessels, which are 

 chiefly situated in the wood, leaves, and petals, but are not 

 found in the bark of trees, nor in herbaceous plants. They 

 Ate called air-vessels, because they contain no liquor, and be- 

 cause large quantities of air are generally found wherever they 

 are placed; and hence they are supposed to be the organs of 

 respiration, or breathing, in vegetables ; but in what manner 

 this function is performed, is not clearly understood. 



III. In the centre of the tree is the PITH, which is of a 

 similar structure in all vegetables ; and is very plentiful in 

 young plants, but, as they ripen, dries up, and appears in 

 smaller quantities, and in aged trees altogether disappears. 

 Between the wood and the pith lies a g-reen-coloured sub- 

 stance, called the corona, or crown, which is said to contain 

 all the parts of young plants in embryo. 



T^ese are the solid parts of plants, which likewise contain 

 fluids or juici's of two kinds: 1. The succus communis , or 

 common sap, is of the same nature in all vegetables, and 

 differs little from common water, except that it sooner be- 

 comes .putrid on exposure to the air. It is supposed to 

 ascend from the root, and to abound in proportion to the 

 humidity of the soil. 2. The succus proprius, or peculiar sap, 

 which varies according to the different plants in which it 

 exists, giving to each its sensible qualities. It appears from 



experiments to proceed from the branches towards the roots, 

 and never in a contrary direction. Capillary attraction is 

 thought to be the cause of the motion of these juices, the 

 continuance of this power being supposed to depend on the 

 evaporation from the leaves : and of late years a vital power 

 assisting the flow of the juices has been ascribed to plants, 

 because their return from the branches to the roots cannot 

 be otherwise explained. 



Every plant is also composed of several external parts, 

 differing from each other in their outward appearance, and 

 which cannot fail to strike the most careless spectator. 

 Many of these parts are themselves compounded, and ob- 

 viously capable of being separated into subordinate divisions. 

 The first grand division adopted by most botanists, is into 

 the root, the body of the plant, and the fructification, or 

 flower wnA.frv.it. The last, or something equivalent to it, is 

 essential to all plants ; the first is visible in almost all, and 

 the second is not wanting in many. 



The ROOT, is stated by Linneus to consist of the radicle, 

 and the descending caudex. The radicle is that fibrous part, 

 which draws nourishment from the earth, and in many in- 

 stances constitutes the whole of the root. The descending 

 caudex is properly part of the stock or body of the plant, 

 which extends itself below the surface of the ground, as the 

 ascending caudex rises above it. That the ascending and 

 descending caudex have precisely the same nature, is evident, 

 from the well-known fact, that if a young tree be inverted, 

 what was before the root will produce leaves, while the former 

 stem throws out radicles. Roots are divided, according to 

 the term of their duration, into annual, biennial, and ptren- 

 nial. The annual and biennial produce flowers and fruit only 

 once, and then soon die ; the former passing through all the 

 stages of vegetable life in one season ; the latter throwing out 

 roots and leaves the first year, but not completing the fructi- 

 fication till the next. The perennial root has within itself a 

 principle of continued life, and gives being to new flower* 

 and seeds year after year, to an indefinite length of time. 

 Of the roots that are called perennial, some are truly, others 

 imperfectly such. In the true perennial root, the descending 

 caudex and the radicle preserve the same individual organi- 

 zation, and increase in size as long as the plant continues to 

 flourish. The imperfect perennial, are, the bulbous and 

 the tuberous, which perish after producing the bulbs, the 

 tubers or tubercles, which are to be the parents of future 

 plants. 



The BODY of the plant springs from the root, and is ter- 

 minated by the fructification. It is called by Linneus the 

 herb, and according to him consists of the trunk, the /eaves, 

 the fulcra, props or supports, and the hybcrnttcula, or buds. 



The FRUCTIFICATION is a temporary part of the vege- 

 table, designed to perpetuate the species, by producing a 

 perfect seed, in which is contained the rudiment of a plant 

 similar to that by which it was generated. Its essential parts 

 are the stamen and the pistil ; the former corresponding with 

 the male, and the latter with the female, in the animal king- 

 dom. The stamen consists of the filament and the anther ; 

 the pistil, of the yemu or seed-bud, the style, and the stigma. 

 They are generally protected by two coverings, the outward 

 called the calix, and the inward the corolla; but in many 

 kinds of plants, either the one or the other, and in some both 

 of them are wanting. The pistil, in the last stage of its 

 growth, is the parent of the seed or seeds, which are either 

 naked, or inclosed in a pericarp, or seed-vessel. The recep- 

 tacle or base on which the fructification is situated, is com- 

 monly considered as one of its parts ; and in many plants 

 there is a nectary or Uuuey-cup connected with it. 



