bium_, _Brassica Rapa_, and _Passiflora
quadrangularis_.

[Illustration: FIG. 94.--Distended pod of _Sinapis arvensis_ bearing in
the interior stalked flower buds.]

In Bromfield's 'Flora Vectensis,' p. 35, the following account is given
of an abnormal development in _Cardamine pratensis_: "On the lower part
of the corymb were several seed vessels on pedicels changed from their
usual linear to an ovate elliptical figure, so as to resemble a
silicula. These, on being opened, were found to contain petals of the
usual colour, which in the pods above had burst from their confinement
and appeared as semi-double flowers; the valves of the pod answering to
the true calyx. * * * From their verticillate arrangement it is evident
that these petaloid expansions were not transformed seeds, but simply a
development of the common axis within the ovary into an abortive whorl
of floral organs, besides which there were evident rudiments both of
stamens and germens in the centre of the bundle." Baillon[182] also
records a case of the same nature in _Sinapis arvensis_.

[Illustration: FIG. 94*.--Portion of the interior of the silicle in
_Cheiranthus Cheiri_, showing adventitious pod in the place of an
ovule.]

[Illustration: FIG. 95.--Adventitious pod from fig. 94, enlarged.]

Here, too, may also be mentioned the presence of an adventitious siliqua
within the ordinary one attached along the same line as the ovules, and
partially divided by a replum into two cavities. In this case there was
nothing to indicate the presence of floral envelopes (figs. 94, 95). A
similar occurrence has been brought under my notice in some grapes which
were observed to be cracking before they were perfectly ripe, and in
which adventitious fruits were found within the parent grape, occupying
the position of seeds (figs. 96, 97).

Similar anomalous growths are noticed under the heads of Substitution
and Prolification.

=Formation of stamens within the cavity of the ovary.=--The only
instance of this that has come under the author's observation occurred
in some flowers of _Baeckea diosmaefolia_, Rudge, for an examination of
which he is indebted to Mr. Bentham.

[Illustration: FIG. 96.--Section of Barbarossa grape showing
adventitious grape in the position of a seed.]

[Illustration: FIG. 97.--Grape with supplementary fruit in the interior]

In the normal flower there is a turbinate hollow calyx, whose limb is
divided into five serrated lobes; alternat