Fig. 405.—Transverse section of a silicula with narrow replum.
◯>>: Brassica (Cabbage). The seeds are placed apparently in one row in each loculus (Fig. [398] C); the style is long and round; the valves have only 1 strong, longitudinal rib.—Melanosinapis (M. nigra, Black-mustard); the style is compressed, two-edged; the valves of the siliqua are one ribbed.—Sinapis (Mustard); quadrangular or flat style (in which in most cases there is a seed) and 3–5 strong, longitudinal ribs on the valves.—Eruca differs from Brassica by the shorter siliqua, broad, sword-like “beak” and seeds in two rows.
◯= (Fig. [399]): Cardamine (Bitter Cress) has a long, linear siliqua, with flat, unribbed, elastic valves. The leaves are most frequently pinnatifid or pinnate. C. pratensis reproduces by buds formed in the axils of the leaves.—Arabis (Rock Cress); Matthiola (Stock); Cheiranthus cheiri (Wallflower); Barbarea (Winter Cress) (double-edged, quadrangular siliqua); Nasturtium (N. officinale, Water-cress); the siliqua of the latter genus is in some species short, in others long.
Fig. 406.—Thlaspi arvense.
Fig. 407.—Silicula of Capsella bursa-pastoris.
◯‖ (Fig.[400]): Sisymbrium (Hedge Mustard) the valves of the siliqua are 3-ribbed.—Erysimum; Hesperis; Schizopetalum (with fimbriate petals).
4. Fruit jointed (Lomentaceæ). The fruit is divided by transverse walls into as many spaces as there are seeds, and dehisces at maturity, generally transversely, into a corresponding number of nut-like joints (“articulate-siliqua.”)
◯=: Crambe (Kale, Fig. [408]). The fruit has only 2 joints. The lower one resembles a short, thick stalk, and is barren, the upper one is spherical, and has 1 seed.—Cakile (C. maritima, Sea-kale); the lower node is triangular, 1-locular, the upper one more ensiform, 1-locular (Fig. [409]).