[Illustration: FIG. 141.--Leafy ovules, &c., _Trifolium repens_.]
In a species of _Triumfetta_ (see p. 260), of which I examined dried specimens, the ovary was open and partly foliaceous; it bore on its infolded margins ten erect leaflets, representing so many ovules; each leaflet was conduplicate, the back being turned towards the placenta.
[Illustration: FIG. 142.--Leafy ovules of _Trifolium repens_, showing formation of nucleus, &c. After Caspary.]
On the other hand, there are cases in which the leafy coat of the ovule, in place of being a distinct organ, seems to originate from the margin of the carpellary leaf itself--to be, as it were, a lobule or small process of the carpel, and not an absolutely new growth. Thus, Planchon[274], from an examination of some monstrous flowers of _Drosera intermedia_, was led to the inference that the ovules are analogous to hairs on the margins of the leaves. This acute botanist was enabled to trace all the gradations between the simple cup formed by the confluence of four glanduliferous hairs and the concave leaf and the perfect ovule.
Brongniart[275] records ovules of _Delphinium elatum_ existing in the form of marginal lobes of the carpellary leaf itself; so that each ovule corresponds to a lobe or large tooth of this leaf, the funiculus, as well as the raphe, being formed by the median nerve of the lateral lobe. M. Clos[276] mentions a similar instance in _Aquilegia Skinneri_; and another is figured in Lindley's 'Elements of Botany,' p. 88, f. 180.
[Illustration: FIG. 143.--Portion of an open foliaceous carpel of _Delphinium_, with ovules on the lobules.]
Cramer[277], from an examination of several ovular malformations, as well as from the investigation of the mode of evolution of the ovules, is led to a similar conclusion with reference to the production of ovules from the modified lobes of the carpellary leaf. Figs. 143-145, copied from Cramer, show how the nucleus of the ovule is formed as a new growth from the surface of the lobes of the leaf in _Delphinium elatum_.
[Illustration: FIG. 144.--Section through marginal lobe of carpel (_Delphinium_), showing the nucleus (_n_).]
[Illustration: FIG. 145.--Section through marginal lobe of carpel, showing nucleus and tegument (_Delphinium_).]