have long been noticed as
being very prone to present this change. Mohl[346] remarks that, in the
transformation of the stamens to the pistil in the common houseleek, the
filament of the stamen generally preserves its form, the anthers alone
undergoing change. At other times, however, the transformation takes
place at the same time, both in the filament and in the anther. When the
stamens are numerous some of them remain in their normal state, while
others, and especially the inner ones, undergo a change. Sometimes all
the stamens are changed simultaneously, while at other times some of
these organs may be found in which the anther is partially filled with
ovules, and partially with pollen.

In the accompanying figures (fig. 165, _a-h_) a series of intermediate
stages is shown between the ordinary stamen of _Sempervivum tectorum_
and the ordinary carpel, from which it will be seen that the filament is
little, if at all, affected, and that in those cases where there is a
combination of the attributes of the stamen and of the pistil in the
same organ the pollen is formed in the upper or inner surface of the
leaf-organ, while the ovules arise from the opposite surface from the
free edge, (_b_, _c_, _d_, _e_, _f_, _g_).

In a drawing made by the Rev. G. E. Smith of a malformed flower of
_Primula acaulis_, and which the writer has had the opportunity of
examining, the stamens are represented as detached from the corolla, and
their anthers replaced by open carpels, with ovules arising, not only
from their edges, but also from their surfaces, while the apex of the
carpellary leaf was drawn out into a long style, terminated by a
flattened spathulate stigma.

_Delphinium elatum_ is one of the plants in which this change has been
most frequently noticed.[347]

[Illustration: Fig. 165.--_Sempervivum tecotorum._ _a._ Normal stamen.
_h._ Normal carpel. _b_, _c_, _e_, _f_, _g_. Structure partly staminal,
partly carpellary. _d._ Transverse section through _c_, showing pollen
internally, ovules externally.]

In willows the change of pistils into staminal organs has been
frequently observed. In _Salix babylonica_ Prof. Schnizlein has
described various transition stages between the carpels and the stamens,
and in one instance, in addition to this change, a perfect cup-shaped
perianth was present, as happens normally in _Populus_[348]. Mr. Lowe
also records the conversion of stamens into ovaries in _Salix
Andersoniana_, and this by