s; others,
though less frequent, are of more interest. Fusion of two or more
flowers in association with prolification is especially common in
cultivated specimens of _Digitalis purpurea_; the uppermost flowers of
the raceme become fused together so as to form one large, regular,
erect, cup-shaped corolla, to the tube of which the stamens are
attached, in greater number than ordinary, and all of equal length; the
bracts and sepals are confusedly arranged on the exterior of the flower;
while in the centre, in the place usually occupied by the pistil, there
rises a conical prolongation of the axis, bearing at its outer or lower
portion a number of open carpels, provided, it may be, with styles and
ovules; these enclose an inner series of scale-like bracts, from whose
axils proceed more or less perfect florets; so that in the most highly
developed stage a perfect raceme of flowers may be seen to spring from
the centre of a cup-shaped regular flower, whose lobes show its compound
character. All intermediate stages of this malformation may be found
from cases where there is a simple fusion of two flowers with a second
verticil of carpels within the outer, up to such cases as those which
have been just mentioned. It is worthy of special remark, that in all
these cases the flowers at the uppermost part of the raceme are alone
affected, and that, in addition to the prolification, there is fusion of
two or more flowers, and regularity in the form of the compound corolla
and stamens.

The calyx of a prolified flower is either unchanged, or it is modified
in harmony with the changes in the central part of the flower. If the
ovary be normally superior or free from the calyx, then the latter is
comparatively rarely altered; for instance, in proliferous pinks
(_Dianthus_) the calyx is seldom affected, except, indeed, in those
instances where the floral axis is prolonged, and produces from its side
a successive series of sepals, as in what is called the wheat-ear
carnation; but though these instances may be, as I believe, an imperfect
degree of prolification, they do not affect the general truth of the
above opinion, that the calyx, if it be free from the ovary, is but
rarely changed in a prolified flower; but that this is not a universal
rule is shown by proliferous flowers of _Geum rivale_, where the sepals
are usually large and leaf-like, as they likewise are frequently in
proliferous roses and pears.

[Illustration: FIG. 64.--Pr