Cakile Mill.

Scientific Description

Common name. Sea-rockets. Family Brassicaceae.

Habit and leaf form. Glaucous herbs. Plants succulent. Annual, or perennial (rarely). Leaves cauline. Stem internodes solid. To 0.8 m high (or decumbent). Xerophytic (maritime). Leaves small to medium-sized; alternate; spiral; fleshy; petiolate; non-sheathing; without marked odour; simple; epulvinate. Leaf blades dissected to entire (deeply pinnatifid to reduced); when dissected, to deeply pinnatifid; pinnately veined; cross-venulate. Leaves without stipules. Leaf blade margins entire, or serrate, or dentate. Leaves without a persistent basal meristem. Leaf anatomy. Hairs absent; glandular hairs absent; complex hairs absent. Branched hairs absent. Extra-floral nectaries absent.

Reproductive type, pollination. Fertile flowers hermaphrodite. Unisexual flowers absent. Plants hermaphrodite.

Inflorescence and flower features. Flowers aggregated in ‘inflorescences’; in corymbs, or in racemes. The terminal inflorescence unit racemose. Flowers pedicellate; ebracteate; ebracteolate; small to medium-sized; more or less regular, or somewhat irregular. The floral asymmetry involving the perianth. Flowers 2 merous; cyclic. Floral receptacle with neither androphore nor gynophore. Free hypanthium absent. Hypogynous disk present; of separate members. Nectariferous glands 4. Perianth with distinct calyx and corolla; 8; 3 -whorled (K 2+2, C 4). Calyx present; 4; 2 -whorled; polysepalous; erect; decussate; regular. Sepals lateral sepals saccate. Corolla present; 4; 1 -whorled; alternating with the calyx; polypetalous; imbricate, or contorted; regular; white, or pink, or purple (or lavender). Petals clawed. Androecial members definite in number. Androecium 6. Androecial members branched (in that the inner whorl of 4 is derived from only 2 primordia); free of the perianth; markedly unequal; free of one another; 2 -whorled (2+4). Androecium exclusively of fertile stamens. Stamens 6 (2 outer and 4 inner); tetradynamous; all more or less similar in shape; hypogynous, on receptacle, outer stamens lateral. Filaments not appendiculate. Anthers basifixed; non-versatile; dehiscing via longitudinal slits; introrse; unilocular to bilocular; tetrasporangiate; unappendaged. Pollen shed as single grains. Gynoecium 2 carpelled. The pistil 2 celled. Gynoecium syncarpous; eu-syncarpous; superior. Ovary plurilocular; 2 locular. Locules secondarily divided by ‘false septa’. Gynoecium transverse. Ovary sessile. Gynoecium stylate. Styles 1; apical. Stigmas 1 (or 2); 1 - lobed (small, capitate); capitate. Placentation parietal. Ovules (1–)3–50 per locule; with ventral raphe; non-arillate; anatropous.

Fruit and seed features. Fruit 12–27 mm long; non-fleshy (corky); lomentaceous (the upper joint breaking off, the lower persistent); a silicula (of two unequal, one-seeded joints); 2–3 seeded (1 in valve and 1(X-)2 in beak). Seeds scantily endospermic, or non-endospermic; not mucous; small to medium sized. Embryo well differentiated. Cotyledons 2; folded; accumbent; conduplicate. Embryo bent.

Physiology, biochemistry. Mustard-oils present.

Special features. Fruit body distinctly differentiated into valve and beak regions. Beak containing seeds (usually 1 seeded). Replum present and complete. The inner (lateral) pair of sepals saccate basally for nectar storage. Petals not peculiarly elongated as in Stenopetalum. Nectariferous glands lateral and median.

Etymology. From the Arabic qaquelleh, said to be the name of the plant.