Under this head may likewise be mentioned those cases in which the normal, or at least the typical symmetry of the flower is restored by the formation of parts usually suppressed; thus Moquin cites an abnormal flower of _Atriplex[228] hortensis_ described by M. Fenzl as having a true calyx within the two bracts that usually alone encircle the stamens. Adanson, also cited by Moquin, found a specimen of _Bocconia_ with a corolla. _Arum maculatum_ has likewise been met with provided with a genuine perianth as in _Acorus_ and other Orontiads. The unusual development of the sexual organs in diclinous flowers has been alluded to under the head of heterogamy, and other cases where the symmetry of the flower is rendered regular, by the development of parts ordinarily suppressed, will be found in the chapters relating to deviations from the usual number of organs.
This change, or rather this persistence of a form that is usually transient, is generally accompanied by some other alterations. Change of direction, as has been already mentioned, is one of the most common of these; separation of the petals (_Antirrhinum_, _Verbascum_, &c.), and even their appearance in leaf-like guise, are not infrequent (_Delphinium_, _Antirrhinum_, _Verbascum_, &c.) At other times multiplication or increased number of the whorls of petals takes place, often, but not always, at the expense of the sexual organs of the flower. Perhaps even more frequent is the increased number of parts in the same whorl in cases of regular peloria; thus, in the Pelargoniums before alluded to, the parts of the flower are frequently regulated by the number six instead of five.
This form of peloria is most generally met with in flowers that are placed at the end or in the centre of the inflorescence, or in such flowers as occur singly at the end of the flower-stalk, as in _Tropæolum_, _Viola_, &c. It would hence seem as if the freedom from pressure or restriction on one side allowed the flower to develop equally in all directions, and thus to produce regularity of form.
It is obvious, from what has been before said, that the process of fertilisation is in many cases interfered with and altered by the change in the conformation or the flower.