XII. on the Fructification of Seeds

Philosophical Magazine Series 1

ISSN: 1941-5796 (Print) 1941-580x (Online) Journal homepage: http://www.tandfonline.com/loi/tphm12

XII. On the fructification of seeds

Mrs. Agnes Ibbetson

To cite this article: Mrs. Agnes Ibbetson (1818) XII. On the fructification of seeds , Philosophical Magazine Series 1, 52:244, 81-88, DOI: 10.1080/14786441808652010

To link to this article: http://dx.doi.org/10.1080/14786441808652010

Published online: 23 Jul 2009.

Submit your article to this journal

Article views: 2

View related articles

Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=tphm12

Download by: [Wilfrid Laurier University] Date: 23 June 2016, At: 04:31 sl ]

XlI. On the Fructification of Seeds. By ~[rs. AGNi~s IBEETSON. To ]~[r. Tilloch, SIR, m I snow;En in my last letter the formation of the hearts of seed in the roots of a plant. I showed also its progress up the alburnum vessels, and its entranee into the bag of the seed, the contour of the bag being really formed of that line of life which ties the hearts of the seeds together as they mount from the root. See fig. 1. I have before given many specimens of the manner in which the ~eeds are half filled by" the juices of the atmosphere; then completed by a powder flowing upwards from the root ;--there Istopped. I shall now give the next process, which always fol- lows directl?j ; viz. " the fructification of the seeds ;" that i% tile conveying the powder of the pollen when dissolved in the juices of the pistil down to the seeds, allowing each vessel to enter each different seed, and bestow its quantnm of matter on all by turns, This takes place as soon as the seed has reeeived all that which may be eatled its nutriment; and is so different from the fol~ lowing process, that there is no fear of confounding them to;. gerber. Tiffs last operation takes place as soon as the flower is full blown, and therefore arrived at its greatest perfeetion. The nectareous juice is then seen by the naked eye to mount the pistil, and settle in a large drop on the stigma: this it doth each sunny day; and even if the flower is turned downwards, (like a campanula,) still the drop appears to hang and never to fall, but returns within the style down the pistil, into the seel'et neetary, where it re'~ains all night, and reappears next morning in the same situation on the stigma till the pollen is ripe; when~ the dust falli.~g on the stigma, the various apertures thus impressed receive and secure it, and it remains there visibly till it is completely dissolved. That any one should deny the sexual system~ who has regn, larl?ldissecledflowe, rs and plants (espeeiallyif done progressively) ~ Downloaded by [Wilfrid Laurier University] at 04:31 23 June 2016 I can never believe. That the pistil is formed to receive and re- duce the ,flower 9[" the pollen, which clings to it~ and that it the'n- carries the mixt juice down to the little branch in the heart of-the seed, vivifying and exciting its growth,~is certainly true : and let the different figures of the flower be ever so various in this respect, it will be exactly the same in its result. This constant progress tvke plac% and the whole progressive move- ments succeed each other in constant routine. Nor can I con- ceive how botanists could reconcile the doubt tht~y made wi~h l'espect to the trough in the style and stigma, and theretbre to Vol. 52. No. 24,~..4ug. 1818. F its 82 On the Fvuct~cation of Seeds. its corn,eying down the joint juices of the pollen and pistil mat- ters, when they saw and acknowledged the rising of the juice of the pistil to the stigma in that beautiful drop before impregnation. Would not the same trough serve the purpose for the fall- ing liTlid, that it did for the rising one ? And yet all botanists acknowledge the first, but many deny tile last, and believe that there is room for the pistil juice, and not for the same when the pollen powder is dissolved in it, though the style is then infinitely increased and inflated. The flower, let it be ever so various in appearance, is invariable in having the summit and style (if it has any) above the seed- vessel (see fig. 2) ; and in these parts being in one connected pillar With the secret nectary; while the open neetarv is always at the exterior of the pillar, but standing perfectly aloof. "If the stamens appear united with the pistil, it is only so to appearance; they are never fastened but to a skin which is connected with the cylinder below, and can'ies on the vessels of the stamen to the wood part, and only lies against the pistil. Sueh is the stamen of theq ~Iuilegia, (see fig. 3,) and the stamens of the .IF[alva and ~ola, &c. which I have not room to give. The pistil is then unconnected with every other part, but those just mentioned. The stamens when ripe throw their pollen by many different methods on the stigma. The various forms of the pistil proclaim that it was made to receive, secure and dissolve the powder so bestowed. The stigma is either covered with innumerable short thick hairs, which to the eye give it the appearance of velvet, hut when greatly magnified, show that each vessel has several apertures to take in the powder, while the points secure the balls of the stamen, till they burst with the moisture of the pistil. Tile dust is then received into these innumerable apertures, which empty themselves into the interior in a gutter, which runs all down the style to the seeds. But if the stigma, instead of resembling the pistil of the Ca- lumbine, is like the flower of some of the Telrud!lnamia silic~t- losa order, then the stigma swells above, so as to overtop the

Downloaded by [Wilfrid Laurier University] at 04:31 23 June 2016 style, as in the Iberis Erysimum, (fig. 4.) &e. while the nume- rous corresponding apertures take in the powder at d d d, and send it when dissolved down to the seeds, (see fig. 4.) In the Chelidonium, a gutter is carriedI round below the surface, which receives all the juice the hairs bring it, as at fig. 5. (a a) in regular rows; and the whole centre is one deep trench in the mid- die, by which, there being no ~tyle, the juice is at once carried in three regular cuts down to the seeds. In the Cheiranthus, the seed-vessel being a sort of flattened triangle (fig. 2) ; tim summit at 2 XX has a bending in the middle ; the large orifice is therefore in the centre only: while at fig. 2. aa is ~the summit ; bb On the Fruct~cat~on o/Seeds. 83 b the seed-vessel ; cc the hidden neetary; dd the rising up of the hearts of the seeds before they enter the seed-vessel, and place themselves at e e in the seed. The next sort of pistil is that which opens the stigma into various divisions. This most simply declares its office, sinee the pistil never divides till the pollen balls are ready to explode. This is seen in the Iris, where the powder or dust is discovered all the way down the passage (fig. 5. e e e,) beginning to pass into it at dd. No pistil so puzzled the botanist at first as the Iris. It was long disputed which was the female : but nothing is so easy as fixing on that part, as it is always the middle pillar, (see fig. 5.) b b the seed-vessel; c c the seeret neetary ; 0"¢" the stigma; and g g the style which conveys the joint julees in three rows to the seeds. In many of the stigmas formed in this manner, there appears no opening till just before the whole is con- eluded and that the stigma is covered with balls, as at B C "- then, .if carefully watehed~ the stamens will be seen to burst one after the other, so as to surround the stigma with a sort of cloud; and this is almost always at noon. This accounted to me for a beautiful sight I never saw but twice, though I have often watched for it--the flowing of the pollen in a field of rye-grass. A cloud came on, whieh at first I eould not understand, and fell on the female flower and leaves around. I had just come for the purpose of examining whether the seeds were fructified: I found they were not; but two days after when taken up,the line of life appeared along the heart and seed, and the seed-leaf had begun to grow. In many stigmas that divide, the stamens fall so completely into the aperture which the separation has made, as to be themselves dissolved and sent down the style to the seeds. Authors have said that it isstrange that the dust of the pollen is never discovered in the passage, and that it never tints with its eolour the interior of the style. But this is certain!y a great mistake, for I have repeatedly seen it do so. I have just mentioned a proof of this ; and the Rhododendron is another instance where the passage is so open that the bails enter and are soon absorbed,

Downloaded by [Wilfrid Laurier University] at 04:31 23 June 2016 and the juice carried down to the seeds. But in general the cases of the pollen are taken for the powder itself; the inward dust is rarely of any other colour than a very light green or very pale yellow, though the eases are often highly pahlted : and this faint tint is so like the appearance of the juices, that it would produce no change on them if mixed. But when this proves different, the interior of the style gets often coloured, as is seen in the tulip; in whleh though the pollen is a very pale green, yet the stamens are almost black, and often mix their eolour with it, and thus paint the intcrii)r of the style. This also happens to the yellow Iris~ wh~re the eoloured stamens impress their tint F 2 withia $4 On the Fructifeatlon of Seeds. within the passage of the three leaves, which I have repeatedly discovered deeply tinted, though affected principally by means of the outward skin of the stature b which in the rubbing has got mixed with the pollen powder. The first thing to be assured of, is the mark which proves that the seed is really perfected. This sign is most plain, and is the same in every seed, never varying. It is a li~e which passes through the heart and seed, and then out again, touching that little branch which the eoreulum brought fi'om the root with a sort of loop ; the vessel then runs to the next seed, and so on, (see fig. 6.) gg are the seeds before imprcglmtion, h h after, It will be seen that at i i i the heart has not vet risen to the top of the Seed, where it must get before the line can pass. There are often many stigmas and styles to one seed-vessel: the number of divisions is proportionate;--bnt this I shall leave till I come to show the periearp, as the cause of this arrangement is exquisitely beautiful ; formed and adapted by nature for the purpose of dh~.inishlng the space required, and secreting and confining in as little room as many seeds as possible. The art with which this is done (though the seeds change their form three or four tin:es) is ~nost wonde~fid, and the deal of space left to give them free liberty can never be enough admired; some requiring to lay a part of their time in liquid, when the seeds are left quite in a trough, which they only fill up with solid matter when their outward cases grow. The manner in wbieh the middle pillar of the flower is left,~at such perfect liberty that it may have room for every motion, and for every increase, and also to admit the insect to seek the open nectary~also merits particular observation. But the astonishing care that has been taken to prevent the possibility of its ,~pproaehing the secret nectary cannot be sufficiently adufired ; as that would at once be robbing the fl~wer of its filture perfect seed, by preventing its impregnation. i have repeatedly placed the pollen on different st;gmas, to show e:~aetly the time the seeds will be in receiving this appearance, ehown at fig. 6, h h. Few seeds require more that three days ;

Downloaded by [Wilfrid Laurier University] at 04:31 23 June 2016 the stone plants will, il~deed, sometimes require a Iortnight or three weeks, but rarely more : it is a great mistake to suppose that so much time is neeessarv. When the whole is performed, a ~Jtal suspension of action ta'kes plaee till the seed gets buried i~ the ground. The earth then forms a new stimulus. But~eeds will rarely pass beyomt a certain point till they fall ; and the in- ~erior of the seed always begins to grow two or three days at ~(urthest a~ter the line has passed up the seed, because the oxygelt t.i~c,y directly yield is absolutely necessary to the grdwth of th~~. embryo, which is now ineraaaing most wonderfully. Tl;e idea of the seed-leaf yielding food instead of gas was the most On the Fruct~cat~on of Seeds. 85 most strange and eontradlctory imaginable; since the nourishing vessels are visibly made fbr the latter purpose ; but leaves from the first mor~lent yield tlaeir oxygen, as may be known by theh' dissection. As ~o the manner cf the impregnation of the seed'c,, I have tried them in almost every class and order, but never did- covered an~/difference in this re'~pect. But I am now trying in different sets of plants whether they vary in any way; such as fresh-water plants, sea-weeds, sand-weeds, &c. Ill my next letter I shall give tLe progressive passage ¢fler the impregnation of a plant to its growth in the earth, with all the intervening step~ never l~efore shown~ and most truly curious. It is always better, for dissection, to trust to the indigenous or flowers of the country ; it is certain that, the spiral not being ~o perfect in exolics, its functions are not performed so well. I }lave now before me above forty different sorts of pistils, but they all proclaim the same law and mode of proceeding. The stigma of the Pentandria d@ffnia plant is a very curious one, formed of bubbles, which visibly show the absorption of the powder and its reduction into tile juices which tint the interior, through the trough of the st.~le (see fig. 9); as is also the pistil of the Glecthoma (fig. 9 X), which has long hairs, to which the halls adhere till they explode, yielding their extremely fine dust bv a sudden appa,'ent electrical effect, when tile absorption ta~:en place, and it is quick and immediat¢. It is quite a mistake of G~ertner to say, that when barren and fertile seeds are mixed together in the same seed-vessel, the whole becomes nugatory. There is no seed-vessel that has no~ both sorts in the same periearlJ'ium; but they are imperfect from different causes, easily perceived : from the heart not reaching the seed,~ from the seed not being impregnated ; that i% the line of life not passing through the eorcnlum,~ from the nourishmen;, dying awaybefbre it can reach the seed. Every seed-vessel shows at first many seeds, even those that never perfect but one or two. This is admirably seen in the chesnut,

Downloaded by [Wilfrid Laurier University] at 04:31 23 June 2016 which almost always has ~ix when tile periearp is raider the bud; they go off by degrees, mad at last one or two only are completed. As to the proof that the mixture of the pollen is the cause of the impregnation of the seeds, let the evidence be only fairly ex~ amined, and no one can disbelieve it. A bedof female plants of the dioieous tribe has been set, and kept from the approach of staminiferous flowers, and perJect seeds have notwithstanding been got from it. This has been brought forward as a proof of the Jalsehood of the sexual ~ystem,--without the female plants being examined~ to see whether there were not males concealed F 3 among 86 On the Fruct~cation of &eds. among them, which is almost always the ease. This at once renders that trial nugatory. Then it must be reeolleeted that most flowers can be impregnated from pollen of the same species. This is another eause of uncertainty. The only true method, therefore, is trying those plants that never produce, or will hear this mode of management; among whose pistils mnle plants are never found, and that cannot be impregnated from other pollen than their own. There are a few of these: The Palms, the Pistachio nut, the Fig, and two or three more. These have been for years without producing fruit, on the failure of the ma~e plant. 1 had a complete proof of this, which I shall give, as it is in vain to repeat Linn~eus's excellent trials, which are in every botanical book. When I was at Lisbon, in passing to the Caul- ders, about half way I came to a village, where there were at that time many female palm-trees and no male, but in the middle of each tree was placed a branch of the male. I inquired the reason. The man told me he had planted many, and chose them wrong from ignorance, and for )'ears they had given rio fruit, as there were then no palms oll this side of Lisbon ; but Iris children going to Lisbon brought a branch of the male palm, and stuck it in the tree, and that tree gave fruit. The next year he had therefore performed the same to eact b and had always a quantity of dates. At Belle Vue I planted a female Juniper ; and it never had fruit, though there were many male plants within two miles: bt~l: it was placed on a remarkably high hill, where the winds hle~t with violenee. After many years experiment I wished to try a male plant, and placed it near; and I had fruit verysoon after, within two years I think. As to the Fig, it is the only flower that appears to me truly to be made ]br the insect to do the qff~ce, since both parts are confined in a receptacle which is laid open at the proper time. When the insect Cffnips enters the male Fig, it rolls itself in the pollen, then flies to the female, and deposits the powder all round the aperture which nature makes at this time in both fruits. Here at the entrance it inserts its own

Downloaded by [Wilfrid Laurier University] at 04:31 23 June 2016 eggs, and leaves the pollen all round the orifice, which is soon conveyed to the stigma by means of the juice of the pistils, which almost overflow the receptacle with their liquid. By what means will the pollen of the Prim~da yetis, thrown on the Primula vulgaris, make a Cowslip of it the next year, though that flower is so rare in this county of Devon,~and that degenerate and return to its original species, if the trial is no~ repeated? Why will the pollen of the Sweet purple Pea, thrown on a number of white ones, give seed the next year that will bestow a pretty equal number of both colours, and some varie- gated ? On the Fructification of Seeds. 87 gated ? Why is the syngenesian flower capable of receiving the juice of the pistil, which runs up and often even covers the seeds below, without any effect ?--but when it descends with the flower of the stamen, and runs into the seeds with the joint juiees~ why are the seeds directly impregnated ? If the pollen had no effect, how could all this happen ? But of all the seeds~ none will p~rhaps show the whole process more completely than the Fragaria (fig. 10), especially at the seed fig. 11 X : a a is the stigma and style ; b b the heart of the seed, which rises fl'om the root of the plant ; c c the ascent and descent of the juices from the coreulum; ddd is the juice first ascending to the stigma; and e e is the liquid running from the style to the heart of the seed, and carrying the mixed juice : therefore in this seed there is a separate vessel; and one peculiarly adapted to convey the powder and juice through the heart, showing that the pisl;il juices could not do it. Fig. 10 is the seed-vessel, and ddd the part which conveys the corculums up to each seed. I have drawn it completely as it appears, and as a half-guinea glass can show i~. As to the idea that the embryo is formed in the male or sta- mina, it is most ridiculous; for it is far smaller than the embryo of tile seed. Besides, 1 have shown by a progressive picture, that the beginning of the seed proceeds directly from the root~ and that it must be the right partmthe real embryo--since it is never lost sight oftillJi'uctified; this part may therefore he as well called an egg till it has joined its seed. When I said that I knew but of one flower that appeared really to want the assistance of insects, I only meant that ua- ture had made them perfect, but the change of climate had al- tered them :--many exotics that would go on increasing their fi- laroents, are stopped by the alteration of climate, and the weakness of the muscle. It is sometimes the case with our owli flowers in bad seasons ; and in watching, how continually have ! seen innumerable flowers bend down their pistils with a jerk to procure the powder of the stamen! In many of the Lily tribe, I have caught them when bending with a sudden jerk, which had

Downloaded by [Wilfrid Laurier University] at 04:31 23 June 2016 much the appearance of an electrical effect or shoek,~sueh as the pistil of the Orange Lily, or the Hemeroeallis Jhlva, the large white Lily. I have seen the single Camilla Ja/~onica (the pistil of which is sometimes prolonged much beyond the stamen) bend down and sweep the pollen of each stigma in its turn, till it loaded itself with powder. I have also seen in like manner the ./lmaryllisJacoba?a bend down and make end3 stigma take its sh are of the powder: but this moves gently along after the reception of the powder, and not with a jerk. How curiously in the Winter Rose will the stamens (though they all lie around) raise themselves, and turn so many at a time in a contrary direction~ F 4 while 8S On the reluliix Powers (f A/~b,.a while in the Geranium, the pistil is made to bend bv the fila- ments twisting round her! How beautifially does the'Spm'tiura junceum throw off its keel~ that the pistil may have room to sweep round, and'turn its poit~ts to the spreading stamens, which pass between each ! I have watched this, flower after flower, with admiration : for the manner in which it first throws back the banner is most eurious ; the wings then fly apar% and the inward motion of the keel becomes perceptil)le; when the sun striking full on it, it flies open, and the stamens disperse some of their powder. Now at full liberty, the boxes of the stamen open, and the pistil turns round, and one after the other presses between. the two points of the stigma, and thus loads it with powder. I must now stop : My letter is already too long. Fig. 7 is the interior of the flower of the ~4quilegia vulgaris, to show how the hearts of the seeds pass up the stein to the seed-vessel and seeds at ee e, and how the juice passes up from the secret neetary a a'to the stigma b b b, and the pollen up the vessels g g to the stamenff. Fig. S is a single pericarpium and stigma at top. Fig. 5 is the interior pillar of the Iris, &c. The rest I believe I have already explained. I amj sir, your obliged servant, ACN~S !BBETSON, Description of Plate II. No. S. Fig. 9 is the stigma of the Ground Ivy ; the pollen powder within the ballu enters the diminutive holes, when dissolved. At a a in Fig.4 is one of those stigmas which are so much larger than tl~e atyle, and have a gutter running round at a a a, and descending also at b b to the style. Fig. 4 X is the stigma of the Pentandria di~ynia plant ; and c cc the hairs at which the mixed juiees enter the stigma: it has a gutter all round, and one through the middle. Fig. 3 is the manner in whieh the stamens loosely surround the pistil when it is supposed to be fastened to it. B and C

Downloaded by [Wilfrid Laurier University] at 04:31 23 June 2016 two more stigmas. The seeds, fig. 7 X and fig. 2 c c are the shape of the seeds at that time, both impregnated.

XIII. On the Cornparalive Powers of Algebra and ~zlgar Mrith~ melic. By W~LL1AM G~TT~RID6E, Esq. To Mr. Tilloch. slrt,-is you will no doubt acknowledge that in a eommerci~t| country like ours, the true principles of calculation should be thoroughly ?7I:W.MQ{I.Yol.LILl'L.JI. &.2. l'ifI . .,.. "

?ig.Il. 1.

,, 'ne Downloaded by [Wilfrid Laurier University] at 04:31 23 June 2016

.1'.1'

,. . I ( ~ - I

/ /