In Lilium tigrinum, some specimens of which were gathered by Mr. J. Salter, in addition to various degrees of synanthy and other changes, some of the stamens were developed in the form of carpels, adherent by their edges so as to form an imperfect tube or sheath around the normal pistil. Fig. 164 shows one of the intermediate organs from these flowers, in which half the structure seems devoted to the formation of ovules, while the other half bears a one-celled anther. Lindley[342] has also described a case of this kind in a species of Amaryllis.
Fig. 164.—Structure half anther, half carpel, Lilium.
In Saxifraga crassifolia it sometimes happens that mixed with the stamens, and originating with them, are a number of distinct and perfectly formed carpels, wholly separated from the normal carpels, in the centre of the flower. In this particular instance there is usually no intermediate condition between the stamen and the pistil. Guillemin[343] also describes a transformation of the stamens into carpels in Euphorbia esula.
When the anther is involved it may be only partially so, or almost the whole organ may be transformed. As instances of very partial change may be cited the passage of the connective into a stigma in Thalictrum minus, or the passage of the points of the anthers into imperfect styles in some species of bamboo.[344]
In Rosa arvensis similar transformations have been observed of a slightly more complex character than those just mentioned, and passing into more important changes, especially to the formation of pollen within ovules, formed on the edges of an open carpellodic anther ([see p. 186]).
Mr. Berkeley has recorded an analogous case in a gourd in which the stamens bore numerous ovules (p. 200), and Baillon describes another gourd in which certain fleshy appendages surrounding the andrœcium were provided with ovules.[345]
Payer, in his 'Organogénie,' p. 38, mentions a stamen of Dionæa bearing not only an anther, but likewise an ovule.
Sempervivum tectorum and S. montanum, 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.