[Illustration: FIG. 117.--FLOWER OF THE BROMPTON STOCK.]
The Brompton Stock (_Mathiola incana_), and the Ten-week Stock (_M. annua_), differ from the Wallflower principally in the shape of the stigma (see _fig._ 117, _a_). The petals have also rather longer claws, and hang looser, as shown at _b_. The Virginian Stock (_Malcomia maritima_) has a roundish silique, and only one stigma, which ends in a long tapering point. The Candytuft (_Iberis umbellata_) has a short pod or sillicle, which has the appearance of being cut off at the point, and which contains only one seed in each cell; and the outer two petals of the flower are somewhat larger than the inner ones. Many other Cruciferous plants might be described, but I think my readers will have pleasure in seeking them out themselves, and examining them, to discover their points of agreement and of difference; particularly as, though the order is such a very large one, the flowers of all the plants are so much alike, that no one can be in doubt respecting their alliance.
The common Mignonette (_Reseda odorata_) was once included in the order Capparideæ; but it is now made into a little order by itself, called Resedaceæ. The flower, as is well known, is by no means remarkable for its beauty, though it is for its fragrance; but when examined botanically, it will be found well deserving of attention, from the singularity of its construction. It has a green calyx of six sepals, which are only remarkable for being what botanists call linear; that is, long and narrow, and of equal width throughout--a very unusual form for sepals. Within the calyx are the petals, six fleshy, green, heart-shaped bodies; with a hair-like fringe round the lower part, and with the upper part cut into a tuft of segments so different in colour and texture from the lower part, that it is scarcely possible to believe that they are one. This upper part of the petal is called the crest, and it is pure white; the segments into which it is divided appearing to be a great number of delicate little petals growing out of a fleshy heart-shaped disk.
It is worth gathering a flower of Mignonette, and taking off one of the petals to look at it in a microscope; and one of moderate size, which may be bought for 12_s._ at the Bazaars, will be quite sufficient for the purpose. It will then be found that the fleshy part of the petal is as easily detached from the rest of the flower as petals usually are, but that it is so firmly fixed to the crest as to be inseparable without cutting. The disk is, however, dilated and curiously drawn out between the stamens which are inserted in its base, and the petals, as though to form a barrier between them. It will be quite visible when the petals are removed, as it is as firmly attached to the stalk of the flower as the petals are to their crests. Between this elevated part of the disk and the calyx is a green substance which looks like a part of the stalk, but which belongs to the disk. There are twelve stamens, with large orange-coloured anthers, which are at first erect, but afterwards bend forward horizontally; and in the middle of the stamens is the ovary, an oblong hollow cell, with a three-lobed stigma, forming three erect points. Inside the ovary from each stigma runs the kind of nerve called the placenta, and to each nerve are attached three rows of seeds. The substance of the ovary is always soft and leaf-like, even when it becomes a ripe capsule; and though it is greatly swelled out and bladdery, it retains the same leaf-like and somewhat wrinkled appearance to the last. When the capsule is ripe, each of the pointed lobes, which formed its upper extremity, opens down the middle, thus forming a curious three-cornered mouth for the discharge of the seed. The flowers form what is called an upright raceme, springing from a succulent main stem, which is, however, somewhat woody at the base. The plant indeed, though treated in England as an annual, is a shrub in the plains of Barbary, of which it is a native; and even in this country it may be made to assume the character of a small tree, by keeping it during winter in a hothouse or greenhouse. I was very much surprised to find that Mignonette has been introduced barely a century; and it seems difficult to imagine how those of our ancestors who were fond of flower-gardens contrived to do without it. I have only to add that there are several species of Reseda, one of which (_R. luteola_) is a British plant used in dyeing, and is called Dyer's Weed, or Weld.