Page:Cyclopaedia, Chambers - Volume 2.djvu/437

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The Flower of the Plant, for all its Finery, is found to be the Pudendum, or principal Organ of Generation", but the Ul'e of fo much Mechanifm, and fo many Parts has been but little known.— -We fhall inftance in a Tulip.

Its Flower confifts of fix Paula, or Leaves ; from the Bot- tom whereof, at the middle, arifes a kind of Tube called the Piftil; mi around this are difpofed pretty fine Threads called 5f .«»»«, arifing likewife from the Bottom of the Flower, and terminatinginlittle Bunches a-top, a\\'A Apices, replete with a Sue Dud call'd K*n».<— For the further Explanation of the Parts of Generation fee Pistil, Stamen, Farina, &c.

This is the general Structure of the Flowers of Plants, t'no' diverfified infinite Ways, and to fuch degree, thatfome have no fenfible Piftil, others no Stamina ; others have Stamina without any Apices ; and what exceeds all the reft ,fome Plants have no Flowers.— But, allowing the Structure now reprefentedto be, as in effect it is, the moft common 5 and that thefe Parts which feem wanting are ufually only iefs apparent : The Generation of Plants, in general, may be well accounted for.

The Fruit is ufually at the Bafis of the Piftil, fo that when the Piftil fills, with the reft of the Flower, the Fruit ap- pears in its fteid.— Indeed, frequently, the Piftil is the Fruit iffelf; but ftill they have both the fime Situation in the Center of the Flower, whofe Leaves difpofed around the little Embryo, only feem deftined to prepare a fine Juice in their little Veffels, for its Support, during the little Time they lift, and it requires : tho' Mr. Bradley takes their chief Ul'e to be to defend the Piftil, &c.

The Apices of the Stamina are little Capfulse, or Bags full of a Farina or Dull, which upon the Capfuloe growing ripe and burfling, fill out.

M. Tourncfort took this Duft to be only an Excrement of the Food of the Frufr, and the Stamina to be no more than a kind of excretory Ducts, which filtrated this ufelefs Mat" ter, and thus difcharg'd the Embryo-Kant. But Mr. Mor- land, M. Geoffrey, and others, find nobler Ufes for this Duft.

' According to their Syftem, 'tis this Duft that falling on

the Piftil fecundiSes the Grain or Fruit inclofed therein ; and hence they call it the Farina fcecundans. — Thus the Farina fhould be the Male Part of the Plant, and the Piftil the Female.

Mr. Bradley, at the bottom of the Piftil of the Lilly, ob- ferves a Veffel which he calls the Uterus, or Womb, where- in are three Ovaries fill'd with little Eggs, or Rudiments of Seed, like thofe found in the Ovaria of Animals ; which, he adds, always decay and come to nothing, unlefs impregnated by the Farina of the fame Plant, or fome other of the fame Kind.— The Stamina, he fays, ferve for the Conveyance of the Male Seed of the Plant, to be perfected in the Apices ; which when ripe, burfling forth in little Particles like Duft, fome of them fill into the Orifice of the Piftil, and are either conveyed thence into the Utricle, to fecundify the fe- male Ova, or lodg'd in the Piftil, where, by their magnetic Virtue, they draw the Nourifhment from the other Parts of the Plain into the Embryo's of the Fruit, making 'em (Well, grow, &c.

The Difpofition of the Piftil, and the Apices about it, is always fuch, as that the Farina may fall on its Orifice. — 'Tis ufually lower than the Apices ; and when we obferve it to be grown higher, we may conjecture the Fruit has begun to form itfelf, and has no further orcafion for the Male Duft. Add to this, that as foon as the Work of Generation is over, the Mile Parts, together with the Leaves, fall off, and the Tube leading to the Uterus begins to fhrink. Nor muft it be omitted, that the top of the Piftil is always either co- ver'd with a fort of Velvet Tunicle, or emits a gummy Li- quor, the better to catch the Duft of the Apices.— In Flowers that turn down, as the Acanthus, Cyclamen, and the Im- perial Crown, the Piftil is much longer than the Stamina ; that the Duft may fall from their Apices in fufficient Quan- tity on the Piftil.

This Syftem favours much of that admirable Uniformity found in the Works of Nature ; and carries with it all the teeming Char.tfterifticks of Truth ; but 'tis Experience alone niufl determine for it — Accordingly, M. Geoffrey tells us, that all the Obfervations he had ever made, the Plant was ren- dred barren, and the Fruits became abortive, by cutting off the Piftils before the Duft could impregnate them -, which is fince confirm'd by other Experiments of Mr. Bradley.

In many kinds of Plants, as the Willow, Oak, Pine, Cy- prefs, Mulberry-Tree, &c. the Flowers are flerile, and fepa- rate from the Fruit. But thefe Flowers, M. Geoffrey obferves, have their Stamina and Apices, whofe Farina may eafily im- pregnate the Fruits, which are not far off.

Indeed there is fome Difficulty in reconciling this Syftem to a Species of Plants which bear Flowers without Fruits, and another Species of the fame Kind and Name which bear Fruits without Flowers ; hence diftinguilh'd into Male and Female: of which kind are the Palm-Tree, Poplar, Hemp, Hops, Crc.—For how fhould the Farina of the Male, here come to impregnate the Seed of the Female ?

M. Taurnefort cohjeftures, that the fine Filaments, To mentum, or Dowij, always found on the Fruits of 'th e fr Plants, may ferve inftead of Flowers, and do the Office of Impregnation.— But M. Geoffrey rather takes it, that the Wind, doing the Office of a Vehicle, brings the Farina of the Males to the Females.

In this opinion he is confirm'd by a Story in Jevianus Pontams; who relates, That in his Time there were two Palm-Trees, the one Male, cultivated at Brindes, the other Female, in the Wood of Ottrantum, 15 Leagues a-parf that this latter was feveral Years without bearing any Fruit - till at Length riling above the other Trees of the Forefi, fo as it might fee (fays the Poet) the Male Palm-Tree at Brindes, it then began to bear Fruit in abundance.

Here, M. Geoffrey makes no doubt, the Tree then only be- gan to bear Fruit, becaufe in a Condition to catch on its Branches the Farina of the Male, brought thither by the Wind.

For the manner wherein the Farina fecundifies; M.Ceof- frey advances two Opinions.— i Q That the Farina beingal- ways found of a fulphurous Compofition, and full of fubtile penetrating Parts, (as appears from its fprightly Odour) fall- ing on the Piftils of the Flowers ; there refolves, and the fubtileftof its Parts penetrating the Subftance of the Piftil and the young Fruit, excite a Fermentation fufficient to open and unfold the young Plant inclofed in the Embryo of the Seed.— In this Hypothefis the Seed is fuppofed to contain the Plant in Miniature, and only to want a proper Juice to Unfold its Parts and make them grow.

The 2d Opinion is, that the Farina of the Flower is the firft Germ, or Bud of the new Plant, and needs nothing to' unfold it and enable it to grow, but the Juice it finds pre- pared in the Embryo's of the Seed.

Thefe two Theories of Vegetable Generation, the Reader will obferve, bear a drift Analogy to thofe two of Animal Generation: viz.. either that the young Animal is in the Semen Mafculinum, and only needs the Juice of the Matrix to cherifh and bring it forth; or that the Animal is contained in theFemileOvum, and needs only the Male Seed to excite a Fermentation, &c. See Co n cept 1 o n, Genera- tion, &c.

■. M. Geoffroy rather takes the proper Seed to be in the Fa- rina; inafmuch as the beft Microfcopes don't difcover the' leaft Appearance of any Bud in the little Embryo's of the Grains, when examined before the Apices have ftied their Duft — In leguminous Plants, if the Leaves and Stamina be removed, and the Piftil, or that Part which becomes the Pod, be viewed with the Microfcope, e'er yet the Flower be opened; the little green tranfparent Veficute, which are to become the Grains, will appear in their natural Order ; but ftill (hewing nothing elfe but the mere Coat, or Skin of the Grain. If the Obfervation be continued for feverafDays fuccellively, in other Flowers, as they advance, the Veficote will be found to fwell, and by degrees to become replete with a limpid Liquor ; wherein, when the Farina comes to be fhed, and the Leaves of the Flower to fall, we obferve a little greenifli Speck, or Globule, floating about at large.— At firft there is not any Appearance of Organization in this little Body; but in time, as it grows, we begin to diftin- guifh two little Leaves like two Horns. The Liquor dimij nifhes infenfibly, as the little Body grows, till at length the Grain becomes quite opake ; when, upon opening it, we find its Cavity fill'd with a young Plant in Miniature; confifting of a little Germ or Plumula, a little Root, and the Lobes of the Bean or Pea.

The manner wherein this Germ of the Apex enters the

Veficula of the Grain, is not very difficult to determine ,

For, befides that the Cavity of the Piftil reaches from the top, to the Embryo's of the Grains, thofe Grains, or Veficute, have a little Aperture correfponding to the Extremity of the Cavity of the Piftil, fo that the final! Duft, or Farina, may eafily fall thro' the Aperture into the Mouth of the Veffels which is the Embryo of the Grain— This Cavity, or Cica- tricula, is much the fame in moft Grains, and 'tis eafily ob- ferved in Peafe, Beans, &c. without the Microfcope. The Root of the little Germ is juft againft this Aperture, and 'tis thro' this it paffes out when the little Grain comes to germinate.

The Procefs of Nature in the Generation of Vegetables, and the Apparatus the has contrived for that Purpofe are fo curious, and withal fo little and fo lately known among us, that we fhall illuftrate them further with Figures ; taking the Melon for our Example, in regard the Parts of Genera- tion are here very diftinft.

By the way it muft be obferved, that tho' the Melon contains both Sexes, yet the Difpofition of the Organs dif- fers, here, from the general one above rehears'd in the Inftance of the Tulip : In effeft, in the Melon are two diftinft Flowers, or BlofFoms, the one doing the Male Office, the other the Female; which we fhall therefore call the Male and Female Flower,