Fig. 558.—Fruit of Datura stramonium.
A. Fruit a capsule. Nicotiana (Tobacco) has a 2-valved capsule with septifragal dehiscence; the valves separate at the apex; the corolla is funnel-shaped, tubular, salver-shaped or campanulate. The flowers in panicles.—Datura (D. stramonium, Thorn-apple) has a (frequently spiny) capsule (Fig. [558]), which is falsely 4-locular (at the top, bilocular) and opens septifragally with 4 valves. The lower part of the calyx persists as a thick collar (see Fig. [558]). The corolla is funnel-shaped. The flowers are solitary, large.—Hyoscyamus (H. niger, Henbane) has a pyxidium (Fig. [557]) enclosed in the campanulate, completely persistent, thick-walled calyx. The flowers are slightly zygomorphic, and borne in unipared scorpioid cymes. Scopolia (pyxidium); Fabiana (Heather-like shrub); Petunia (slightly zygomorphic flower; funnel-shaped corolla); Nierembergia; Brunfelsia (almost a drupe); Franciscea; Browallia.—Among those with capsular fruits are found the most anomalous forms, which by their zygomorphic flowers and often didynamous stamens present the transition to the Scrophulariaceæ: Salpiglossis; Schizanthus (lobed petals; 2 perfect, and 3 rudimentary stamens).
Figs. 559–561.—Solanum tuberosum.
Fig. 559.—Flower (1/1).
Fig. 560.—Stamen, ejecting pollen.
Fig. 561.—Longitudinal section of seed.
B. Fruit a berry. Solanum (Nightshade); rotate corolla (Fig. [559]). The stamens have short filaments, the anthers stand erect, close together round the style, like a cone in the centre of the flower, and open by pores at the apex (Fig. [560]). S. tuberosum (the Potato-plant); the Potato-tuber is a swollen, underground stem; the “eyes” are buds, situated in the axils of its scale-like, quickly-perishing leaves.—Lycopersicum resembles Solanum in the flower, but the united anthers open by longitudinal clefts and have an apical appendage. The cultivated species, L. esculentum (Tomato), has often a higher number than 5 in the flower, and in the fruit several loculi of unequal size.—Physalis (Winter Cherry); the calyx ultimately swells out in the form of a bladder, becomes coloured, and loosely envelopes the spherical berry.—Capsicum (Guinea Pepper-plant); some species have very large, irregular, rather dry (red, yellow, black) berries, which are unilocular in the upper part.—Lycium (false Tea-plant); the corolla is salver- or funnel-shaped; shrubs; often thorny.—Atropa (A. belladonna, Deadly Nightshade, Fig. [555]); corolla campanulate; the calyx projects beneath the spherical, black berry. The flowers are borne singly.—Mandragora; (Mandrake); Nicandra (ovary often 5-locular).—A small tropical group: Cestreæ (Cestrum, Habrothamnus, etc.) has an almost straight embryo, which may also be found e.g. in species of Nicotiana. Related to the Scrophulariaceæ.