In the description of the botanical construction of the Fuchsia, my readers may have observed, that the ovary is placed below the calyx, and quite distinct from it. The same construction is still more visible in the Œnothera, as the tube of the calyx is very slender, and often more than two inches long, while the ovary is often vase-shaped, and of large size. The calyx of _Œnothera biennis_, the common Evening or Tree Primrose, consists of four sepals growing together in the lower part, so as to form a long tube (_a_ in _fig._ 33), and with the upper part or limb generally in two segments (b), which are bent quite back when the corolla expands, and which may be easily divided with a pin into four. There are four petals in the corolla (_c_), and they are placed so as to wrap over each other at the base. The calyx is lined with the dilated receptacle, and in this lining are inserted the filaments of the eight stamens (as shown at _d_); the stamens having versatile anthers, that is, anthers attached to the filament by the middle, so as to quiver at every breath. The pollen contained in the cells of these anthers feels clammy when touched; and its particles, when magnified, will be found to be triangular, and connected by small threads, a form of construction peculiar to this genus and its allies. The style is long, and the stigma is four-cleft. The ovary (_e e_) is situated at the base of the calyx, and when ripe, it becomes a four-celled dry capsule, which bursts into four valves, opening at top to discharge the seed. The seeds, when young, are attached to the central placenta, and they are quite free from hair or wool of any kind. [Illustration: FIG. 33.—THE EVENING PRIMROSE (_Œnothera biennis_).] The genus Œnothera being a very extensive one, it has been divided by M. Spach, a German botanist residing in Paris, into fourteen new genera; but only one, or at most two, of these genera have been adopted by other botanists. One of these Godetia, which embraces all the purple-flowered kinds, has been divided from Œnothera, on account of a slight feathery appearance on the seeds; whereas the seeds of the true yellow-flowered Œnotheras are naked, that is, without the slightest appearance of any feathery substance or wing. The other genus, Boisduvalia _Spach_, includes only two species, both with pink flowers, which are very seldom seen in British gardens. The generic mark of distinction consists in four of the stamens in these species being shorter than the other four; whereas in the true Œnotheras all the eight stamens are of equal length. As M. Spach’s other genera have not been adopted by any British botanist, it is not worth while troubling my readers with the distinctions between them. The flowers of the yellow Œnotheras only open in the evening, or in cloudy weather; but those of the purple kinds, or Godetias, remain open all day. The leaves in both kinds are alternate. THE GENUS EPILOBIUM. [Illustration: FIG. 34.—EPILOBIUM ROSEUM.]