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 impregna- tion. 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.

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