This genus is well known, by the showy plant often seen in shrubberies, called the French Willow-Herb—(_Epilobium angustifolium_), and the English weed called Codlings-and-Cream (_E. hirsutum_). In this genus, the tubular part of the calyx which incloses the ovary, is quadrangular, as shown at _a_ in _fig._ 34, which represents seed-vessels of _Epilobium roseum_, a very common weed in the neighbourhood of London. The limb of the calyx is four-cleft, and the corolla has four petals; and when these fall off, the ovary assumes the appearance shown at _a_. The quadrangular form is retained by the capsule, which, when it ripens, bursts open into the four valves (_b_), and discharges the seed which was attached to the central placenta (_c_); each seed being furnished with a little feathery tuft resembling pappus, as shown in _fig._ 35. The genus Epilobium is divided into two sections; the plants in one of which have irregular petals, the stamens bent, and the stigma divided into four lobes, as in the French Willow-Herb, and the other showy species; and the plants in the other section having small flowers with regular petals, erect stamens, and the stigma undivided. [Illustration: FIG. 35.—SEED OF EPILOBIUM.] THE GENUS CLARKIA. The calyx in this genus is tubular, with the limb in two or four lobes, as in Œnothera. The corolla is, however, very different, the four petals being unguiculate or clawed; that is, so much narrower in the lower part as to stand widely apart from each other; they are also three lobed. The stamens are very different, only four of them being perfect, and the anthers of the other four being wasted and destitute of pollen; and the stigma is divided into four leaf-like lobes, very different from those of all the other genera included in the order. The capsule is cylindrical in shape, and furrowed on the outside; it is four-celled, and when ripe, it bursts open by four valves. The seeds are quite naked. Among the other genera belonging to this order, I may mention the following: _Gaura_, the petals of which are somewhat unguiculate, like those of Clarkia, but not three-lobed as in that genus; the segments of the limb of the calyx often adhere two together, so as to appear three instead of four; the ovary is one-celled, and the seeds naked: _Lopezia_, which has apparently five irregular petals, though, on examination, one will be found to be a metamorphosed stamen, a four-cleft calyx, two stamens, including the one converted into a petal, and a globular, four-celled capsule: and _Circæa_, or Enchanter’s Nightshade, which has the limb of the calyx apparently in only two segments, and only two petals and two stamens; the capsule is globular like that of _Lopezia_, but it is covered with very small hooked bristles, and it is divided into only two cells, each containing only one seed. CHAPTER V.