Datura L.

Scientific Description

Common name. Thornapples. Family Solanaceae.

Habit and leaf form. Shrubs, or herbs; resinous, or not resinous. Plants unarmed (apart from the fruit). Annual, or perennial; plants with neither basal nor terminal concentrations of leaves. Stem internodes solid. Helophytic to xerophytic. Leaves alternate; spiral; ‘herbaceous’, or leathery; petiolate; non-sheathing; not gland-dotted; without marked odour, or foetid; simple; epulvinate. Leaf blades dissected, or entire; pinnatifid; pinnately veined; cross-venulate. Leaves without stipules. Leaf blade margins entire (and sinuate). Leaves without a persistent basal meristem. Leaf anatomy. Hairs present, or absent; glandular hairs absent, or present. Branched hairs absent. Extra-floral nectaries absent.

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

Inflorescence and flower features. Flowers solitary; terminal (or in the forks of stems or lateral — i.e. leaf-opposed or displaced); pedicellate; ebracteate; ebracteolate; medium-sized to large; regular; 5 merous; cyclic; tetracyclic. Free hypanthium absent. Hypogynous disk present; intrastaminal. Perianth with distinct calyx and corolla; 10; 2 -whorled; isomerous. Calyx present; (3–)5(–9); 1 -whorled; gamosepalous; shortly blunt-lobed; tubular, or urceolate; regular; persistent; non-accrescent. Corolla present; 5; 1 -whorled; gamopetalous. Corolla lobes markedly shorter than the tube. Corolla contorted and plicate; funnel-shaped; regular; green (tube), or white (throat translucent white or coloured). Androecial members definite in number. Androecium 5. Androecial members adnate; all equal; free of one another; 1 -whorled. Androecium exclusively of fertile stamens. Stamens 5 (usually). Staminal insertion near the base of the corolla tube, or midway down the corolla tube. Stamens all inserted at the same level; remaining included (or only slightly exserted); all more or less similar in shape; isomerous with the perianth; oppositisepalous (in lower half of the corolla tube). Filaments appendiculate, or not appendiculate; filiform. Anthers connivent, or separate from one another; basifixed; dehiscing via longitudinal slits; introrse; bilocular; tetrasporangiate. Pollen shed in aggregates, or shed as single grains. Gynoecium 2 carpelled. The pistil 2 celled, or 4 celled. Gynoecium syncarpous; synstylovarious to eu-syncarpous; superior. Ovary plurilocular; 2 locular (above), or 4 locular (below, by equal secondary divisions from the placentae). Locules secondarily divided by ‘false septa’. Gynoecium oblique. Ovary sessile. Gynoecium stylate. Styles 1; attenuate from the ovary; apical. Stigmas 1; 2 - lobed (L). Placentation axile. Ovules 20–50 per locule (numerous); non-arillate; anatropous, or hemianatropous.

Fruit and seed features. Fruit non-fleshy; spinose (or tuberculate); dehiscent; a capsule. Capsules valvular, or splitting irregularly (regularly by 4 valves or irregularly from the apex). Fruit 2–4 celled; 20–100 seeded (usually numerous, several). Seeds endospermic. Endosperm oily, or not oily. Cotyledons 2. Embryo curved (through more than a semicircle).

Etymology. From the Hindi Dhatura; name of D. fastuosa.