Pedaliaceae R.Br.

Scientific Description

Common name. Sesame Family.

Habit and leaf form. Herbs (mostly), or shrubs (rarely). Mesophytic to xerophytic (mostly inhabiting shores and deserts). Leaves opposite (at least below); simple. Leaf blades dissected, or entire; when dissected, pinnatifid, or runcinate; pinnately veined; cross-venulate. Leaves without stipules. Leaf anatomy. Hydathodes present (sometimes), or absent. Stem anatomy. Secondary thickening developing from a conventional cambial ring.

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

Inflorescence and flower features. Flowers solitary, or aggregated in ‘inflorescences’; in cymes. The terminal inflorescence unit cymose. Inflorescences axillary; dichasia or cymes. Flowers bracteate (the bracts with axillary abortive flowers functioning as nectaries); very irregular. The floral asymmetry involving the perianth and involving the androecium. Flowers 5 merous; cyclic; tetracyclic. Free hypanthium absent. Hypogynous disk present. Perianth with distinct calyx and corolla; 10; 2 -whorled; isomerous. Calyx 5; 1 -whorled; gamosepalous (forming a lobed tube); blunt-lobed. Corolla 5; 1 -whorled; gamopetalous; imbricate; unequal but not bilabiate, or bilabiate; spurred (sometimes), or not spurred. Androecium 5. Androecial members adnate (to the corolla tube); markedly unequal; free of one another; 1 -whorled. Androecium including staminodes. Staminodes 1 (the posterior member); non-petaloid. Stamens 4; didynamous; reduced in number relative to the adjacent perianth; oppositisepalous; all alternating with the corolla members. Anthers connivent (in pairs), or separate from one another; dehiscing via longitudinal slits; tetrasporangiate. Pollen shed in aggregates (Sesamothamnus), or shed as single grains; when aggregated, in tetrads. Gynoecium 2 carpelled. The pistil 2–8 celled. Carpels reduced in number relative to the perianth. Gynoecium syncarpous; synstylovarious to eu-syncarpous; superior. Ovary plurilocular; 2–4 locular (morphologically), or 4–8 locular (often, ostensibly, via false septa). Locules secondarily divided by ‘false septa’, or without ‘false septa’. Gynoecium median; stylate. Styles 1; attenuate from the ovary; much longer than the ovary at anthesis. Stigmas 1–2; 2 - lobed; wet type; papillate; Group III type. Placentation axile. Ovules 1 per locule (Josephinia), or 2–50 per locule (to ‘many’); pendulous, or horizontal, or ascending; anatropous.

Fruit and seed features. Fruit non-fleshy (often with hooks, or prickly); dehiscent, or indehiscent; a capsule, or a nut. Capsules loculicidal. Seeds thinly endospermic, or non-endospermic. Endosperm oily. Seeds with amyloid. Cotyledons 2. Embryo straight. Seedling. Germination phanerocotylar.

Physiology, biochemistry. Aluminium accumulation not found.

Geography, cytology, number of species. World distribution: Africa, Madagascar, India, Southeast Asia, Malaysia, Australia. 50 species.

Economic uses, etc. Commercial edible oil from Sesamum (benne).