Fig. 7.—Carpels of the Clematis Vitalba.
The plants composing the genus Atragenè have been separated from Clematis; because they are said to have petals, which the genus Clematis has not. It must not, however, be supposed that the petals of the Atragenè bear any resemblance to what is generally understood by that word. On the contrary, the showy part of the Atragenè is still only a coloured calyx; while the petals are oblong, leaf-like bodies in the centre of the flower, which look like dilated stamens. In other respects the two genera are scarcely to be distinguished from each other.
THE GENUS HELLEBORUS, &C.
The Christmas rose (Helleborus niger) bears considerable resemblance in the construction of its flowers to the Atragenè, for it has a showy calyx, and narrow oblong petals, encircling the stamens in the centre of the flower. The calyx of the Christmas rose is white, delicately tinged with pink, and the petals are green. The carpels are erect and long, swelling out at the base, and each ends in a curved style with a pointed stigma. The Christmas rose takes its specific name of niger (black) from the root, which is covered with a thick black skin. The common Hellebore takes its name of H. viridis, from its flowers, which are green. The carpels of this plant frequently grow slightly together, and their styles curve inwardly.
The British species of Hellebore have no involucre, and the Christmas rose has only two bracts or floral leaves, which form a calyx-like covering to the bud; but the little yellow garden plant, called the Winter Aconite, which was included by Linnæus in the genus Helleborus, has a decided involucre, on which the little yellow, cup-shaped flower reposes, like a fairy bowl upon a leafy plate. The conspicuous part of this flower, like the others, is the calyx, which encloses a number of short tubular petals. This little plant is now separated from Helleborus, and formed into a distinct genus, under the name of Eranthus hyemalis, from its carpels being each furnished with a very short footstalk, by which they are attached to the receptacle, instead of growing upon it as in the other genera. The root is tuberous, or rather it forms a kind of underground stem, sending up tufts of leaves and flowers from the different buds. Thus we often see several tufts of the Winter Aconite growing so far from each other as to appear distinct; but which, in fact, all spring from the same root. The Globe-flower (Trollius europæus), which has a golden yellow, globe-shaped calyx, enclosing a number of small oblong petals, is nearly allied to the Winter Aconite; and the Fennel-flower, or Devil in a Bush (Nigella damascena), agrees with the common Hellebore in the adhesion of its carpels.
THE GENUS ACONITUM.