Vegetable Teratology: An Account of the Principal Deviations from the Usual Construction of PlantsMasters, Maxwell T. (Maxwell Tylden)
Science
Vegetable Teratology: An Account of the Principal Deviations from the Usual Construction of Plants
Masters, Maxwell T. (Maxwell Tylden)
Plants -- Abnormalities
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.
[Illustration: FIG. 62.--Median floral prolification, &c., in flower of
_Delphinium_.]
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