Matthiola W.T.Aiton

Scientific Description

Common name. Stocks. Family Brassicaceae.

Habit and leaf form. Herbs. Annual, or perennial. Leaves cauline. Plants with neither basal nor terminal concentrations of leaves. Stem internodes solid. To 0.1–0.8 m high. Mesophytic. Leaves medium-sized; alternate; spiral; ‘herbaceous’; petiolate (lower leaves), or subsessile (upper leaves); non-sheathing; without marked odour; simple; epulvinate. Leaf blades dissected to entire; when dissected, pinnatifid (sinuate-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 present, or absent (rarely); glandular hairs present; complex hairs present. Branched hairs absent. Complex hairs stellate. Extra-floral nectaries absent.

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

Inflorescence and flower features. Flowers aggregated in ‘inflorescences’; in racemes, or in corymbs. The terminal inflorescence unit racemose. Flowers pedicellate; ebracteate; ebracteolate; small to medium-sized; fragrant; regular; 2 merous; cyclic. Floral receptacle with neither androphore nor gynophore. Free hypanthium absent. Hypogynous disk present; of separate members. Perianth with distinct calyx and corolla; 8; 3 -whorled (K 2+2, C 4). Calyx present; 4 (decussate pairs in 2 whorls); 2 -whorled; polysepalous; erect; decussate; regular. Sepals inner sepals saccate at base. Corolla present; 4; 1 -whorled; alternating with the calyx; polypetalous; imbricate, or contorted; regular; white, or pink, or purple. Petals clawed (claws long). 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, 4 inner); tetradynamous; all more or less similar in shape; hypogynous, on receptacle, outer stamens lateral. Filaments not appendiculate (but the medians branched). Anthers basifixed; non-versatile; dehiscing via longitudinal slits; introrse; unilocular to bilocular; tetrasporangiate; appendaged, or 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 non-stylate (AP), or stylate (K). Styles 1 (or 0); apical. Stigmas 1 (or 2); dorsal to the carpels; strongly 2 - lobed (the lobes dorsally swollen or hornlike); capitate. Placentation parietal. Ovules (1–)3–50 per locule; with ventral raphe; non-arillate; anatropous.

Fruit and seed features. Fruit 45–160 mm long; non-fleshy; dehiscent, or lomentaceous (rarely); a siliqua. Capsules valvular. Fruit 2 celled; 40–100 seeded (‘many’). Seeds 20–50 per locule (‘many’). Seed rows per locule 1. Seeds scantily endospermic, or non-endospermic; not mucous; compressed; small to medium sized; broadly winged. Embryo well differentiated. Cotyledons 2; accumbent. Embryo bent.

Physiology, biochemistry. Mustard-oils present.

Special features. Fruit body with no clear differentiation into valve and beak regions. Replum present and complete; broad. Fruit bilaterally compressed, or terete. The inner (lateral) pair of sepals saccate basally for nectar storage. Petals not peculiarly elongated as in Stenopetalum. Nectariferous glands lateral and median, or lateral only. Valves of the fruit neither winged nor keeled; conspicuously longitudinally veined; longitudinally 1 veined.

Etymology. In honour of Pietro Andrea Matthioli, and Italian physician who wrote a commentary on the works of Dioscorides, Pedacio Dioscoride Anazarbeo.