If the pistil be normally syncarpous, its constituent carpels, if present at all in the prolified flower, become disjoined one from the other to allow of the passage between them of the prolonged axis; thus in some malformed flowers of Daucus Carota gathered in Switzerland (fig. 61), not only was the calyx partially detached from the pistil, but the carpels themselves were leaf-like, disjoined, and unprovided with ovules; between them rose a central prolongation of the axis, which almost immediately divided into two branches, each terminated by a small umbel of perfect flowers, surrounded by minute bracts.[125]
Not only are the carpels thus frequently separated one from the other by the prolonged axis, but they undergo commonly a still further change in becoming more or less completely foliaceous, as in the Daucus just mentioned, where the carpels were prolonged into two lance-shaped leaves, whose margins in some cases were slightly incurved at the apex, forcibly calling to mind the long "beaks" that some Umbelliferous genera have terminating their fruits—for instance, Scandix. Dr. Norman, in the fourth series of the 'Annales des Sciences,' vol. ix, has described a prolification of the flower of Anchusa ochroleuca, in which the pistil consisted of two leaves, situated antero-posteriorly on a long internode, with a small terminal flower-bud between them; and numerous similar instances might be cited.
In this place may also be noticed those instances wherein the placenta elongates so much that the pericarp becomes ruptured to allow of the protrusion of the placenta, although this prolongation is not attended by the formation of new buds. Cases of this kind occurring in Melastoma and Solanum have been put on record by M. Alph. de Candolle.[126] This is a change analogous with that which occurs in some species of Leontice or Caulophyllum, as commented on by Robert Brown. See 'Miscellaneous Botanical Works' of this author, Ray Society, vol. i, p. 359.
If the pistil be apocarpous, and the carpels arranged spirally on an elevated thalamus, it then frequently happens that the carpels, especially the upper ones, become carried up with the prolonged axis, more widely separated one from the other than below, and particularly liable to undergo various petalloid or foliaceous changes as in proliferous Roses, Potentilla, &c.
Fig. 62.—Median floral prolification, &c., in flower of Delphinium.
Fig. 62, copied from Cramer, shows an instance of this kind in Delphinium elatum, where not only is the thalamus prolonged, and the carpels separated, but from the axils of some of the latter which have assumed from the disunion of their margins somewhat of the appearance of leaves, other flowering branches proceed—axillary prolification. If, on the other hand, the carpels be few in number, and placed in a verticillate manner, the axis then generally passes upwards without any change in the form or position of the carpels being apparent, as in a proliferous columbine, figured in the 'Linnean Transactions,' vol. xxiii, tab. 34, fig. 5.
When a flower with the ovary naturally inferior or adherent to the calyx becomes prolified, a change in the relative position of the calyx and ovary almost necessarily takes place, the latter becoming superior or detached from the calyx; this has been already alluded to in Umbelliferæ. In a species of Campanula examined by me, the calyx was free, the corolla double, the stamens with petaloid filaments, and in the place of the pistil there was a bud consisting of several series of green bracts, arranged in threes, and enclosing quite in the centre three carpellary leaves detached from one another and the other parts of the flower, and open along their margins, where the ovules were placed. In other similar instances in the same species of Campanula, the styles were present, forming below an imperfect tube which surrounded the adventitious bud; in another, contrary to what occurs usually in such cases, the ovary was present in its usual position, but surmounted by a bud of leafy scales, enclosed within the base of a tube formed by the union of the styles. A similar relative change in the position of the calyx and the ovary takes place when the Compositæ are affected with central prolification, or even in that lesser degree of change which merely consists in the separation and disunion of the parts of the flower, but which in these flowers appear to be, as it were, the first stage towards prolification. I owe to the kindness of Professor Oliver a sketch of a species of Rudbeckia? showing this detachment of the calyx from the ovary. In a monstrous Fuchsia that I have had the opportunity of recently examining, the calyx was similarly detached from the ovary simultaneously with the extension of the axis. Here the petals were increased in number and variously modified, the stamens also; while in the centre and at the top of the flower, conjoined at the base with some imperfect stamens, was a carpel open along its ovuliferous margins. Such instances as these seem to be the first stages of a change which, carried out more perfectly, would result in the formation of a new bud on the extremity of the prolonged axis.