On the Nature of Double Flowers, and the Methods of producing them.
By Mr. James Meader, Author of the Botanical Part of the General Dictionary of Arts and Sciences.
THOUGH nature in general is pretty constant in her productions, yet in the vegetable kingdom she often sports with an almost unbounded freedom, so as to afford ample entertainment and curiosity, to the penetrating eye of the botanist and florist; and nowhere more so, than in the plenitude of doubleness of flowers. We are wonderfully delighted with any new production in the multiplicity of the flower petals of any plant, whose flowers we have been used to admire in its natural, or simple state; or indeed it may be said, in its proper botanical state. As those we call double flowers are inadmissible in the modern systems of botany, being considered by those who study that science as nothing more than a lusus naturae, and consequently are rejected in the fixing their genera; it would not therefore, I think, be amiss to consider, how it comes to pass that nature has in this cafe been so superabundant in one part of a flower, when it seldom shows a luxuriancy at the same time in the other parts; for in most of the genera whose flowers are naturally single, that doubleness produced either by art or accident, which consists in the plenitude of the petals, is generally to the manifest deficiency of those parts which nature designed for the more immediate purposes of generation: these are the stamina or male parts. And this want is evidently seen in the double stocks and wall-flowers; for the stamina so essential to generation being destroyed by the plenitude of the petals, the consequence is, that the flowers are rendered abortive and barren, through the want of the farina foecundans, or male dust, necessary to impregnate the pistillum, or female organ of generation. Now as the corolla, or flower petals, is allowed by all anatomists of plants to be the termination of the libra or inner bark, it may be supposed, that through the exceeding natural richness and moisture of the earth, the parts of the inner bark may be so much expanded and multiplied, as to contract those vessels which are essential for the production of the stamina, and that so much as to render abortive the functions that nature designed them for; and this before they have arrived to their proper extremity, and thereby one principal and necessary part of the fructification is destroyed: and in order to make up this deficiency, the multiplex petals supply the place of the stamina, and form what we call a double flower.—We frequently see double flowers growing naturally without culture: this is generally in moist rich meadows; they are more rare in dry lands, and we find a dung-hill, or soil artificially enriched, produces not this effect; on the contrary, the flowers are more apt to come single, the luxuriancy extending only into the stalk and leaves. It should therefore seem that moisture has the greatest share in producing the plenitude of flower petals.—Of all those perennial plants whose flowers come double, few of them change again to their original singleness: but the case is different with respect to those which are annual. Double stocks must be raised from the seeds produced of single flowers, but as to double lark-spurs, poppies, &c. their generative parts are not so much destroyed, but that they are capable of bearing feeds, as also the double balsamine. Those which are very double are abortive, but from the semidouble flowers feeds are produced; and the same holds good with respect to double carnations: but as the pistils of those very double ones are generally perfect, and likewise their seed vessels, there seems to be nothing wanting to make them prolific, but the male parts of generation; therefore by applying, and intermixing, single flowers amongst them, the foecundity may be obtained, and the feeds perfected. It is a common practice in the management of seedling beds of carnations, to pull up all the single flowered plants, so soon as they shew. Now I would advise that some of the finest striped single ones be left, not only for the above-mentioned purpose, but also for the chance of communicating some of their fine stripes to the feeds of others. In the compound or radiated flowers, as starwort, sun-flowers, &c. the petals which form the rays, are frequently multiplied so much, as to cover the disc, and are therefore called double; but these kinds generally produce seeds. It may not be improper to remark, that the seeds of stocks, balsamines, &c. if kept two or three years before they are sown, are more apt to come double: this effect may likewise be produced by procuring the seeds from some distance; for the change of air and soil will much promote the plenitude of the petals. But as to the common practice among gardeners, of having single flowers grow among the double ones, particularly stocks, in order, as they think, to impregnate the single flowers, whereby the seeds of them may be more productive of double ones, it is not of the least use; as I have before observed, that the male parts, which are the foecundating principle, are wanting; and therefore the pollen or male dust which the pistillum receives, must be from a single flower.
I am, &c. J. Meader.