Nicotiana L.

Scientific Description

Common name. Wild tobaccos. Family Solanaceae.

Habit and leaf form. Shrubs, or herbs; resinous, or not resinous. Plants unarmed. Annual, or perennial. Leaves basal (usually), or cauline. Plants with a basal concentration of leaves, or 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; simple; epulvinate. Leaf blades entire; pinnately veined; cross-venulate. Leaves without stipules. Leaf blade margins entire (or sinuate or undulate). Leaves without a persistent basal meristem. Leaf anatomy. Hairs present, or absent. Extra-floral nectaries absent. Stem anatomy. Secondary thickening developing from a conventional cambial ring, or anomalous; from a single 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 racemes (raceme-like), or in panicles (or panicle-like). The terminal inflorescence unit apparently cymose. Inflorescences axillary (when solitary); panicle loose. Flowers pedicellate; bracteate; ebracteolate; medium-sized to large; fragrant; regular, or somewhat irregular; sometimes somewhat zygomorphic. The floral asymmetry when noticeable) involving the androecium, or involving the perianth and involving the androecium. Flowers 5 merous; cyclic; tetracyclic. Free hypanthium absent. Hypogynous disk present; intrastaminal. Perianth with distinct calyx and corolla; 10; 2 -whorled; isomerous. Calyx present; 5; 1 -whorled; gamosepalous; blunt-lobed; campanulate (narrowly), or tubular; regular; persistent; accrescent, or non-accrescent. Corolla present; 5; 1 -whorled; gamopetalous. Corolla lobes markedly shorter than the tube. Corolla contorted and plicate, or valvate and plicate; funnel-shaped, or hypocrateriform, or tubular; regular, or unequal but not bilabiate; green, or white, or yellow (greenish yellow), or red (dull), or pink. Corolla members entire (emarginate). Androecial members definite in number. Androecium 5. Androecial members adnate; all equal, or markedly unequal; free of one another; 1 -whorled. Androecium exclusively of fertile stamens. Stamens 5. Staminal insertion near the base of the corolla tube, or midway down the corolla tube to in the throat of the corolla tube. Stamens inserted at markedly different levels, or all inserted at the same level; becoming exserted, or remaining included; didynamous, or not didynamous, not tetradynamous; all more or less similar in shape; isomerous with the perianth; oppositisepalous (in the corolla tube, 1 usually at a different level). Filaments appendiculate, or not appendiculate. Anthers separate from one another; dorsifixed; dehiscing via longitudinal slits; introrse; tetrasporangiate. Gynoecium 2 carpelled. The pistil 2 celled. Gynoecium syncarpous; synstylovarious to eu-syncarpous; superior. Ovary plurilocular; 2 locular. Gynoecium oblique. Ovary sessile. Gynoecium stylate. Styles 1; attenuate from the ovary; apical; becoming exserted, or not becoming exserted. Stigmas 1; 2 - lobed (KPLB); capitate. Placentation axile. Ovules 20–50 per locule (numerous); non-arillate; anatropous, or hemianatropous.

Fruit and seed features. Fruit non-fleshy; not spinose (smooth); dehiscent; a capsule. Capsules septicidal, or loculicidal, or valvular. Fruit (2–)4 celled; 20–100 seeded (numerous, several). Seeds endospermic. Endosperm oily, or not oily. Cotyledons 2. Embryo curved (through more than a semicircle).

Special features. Corolla tube exceeding the calyx.

Etymology. After Jean Nicot (1530–1600), French ambassador to Portugal who sent seeds of the tobacco plant to France in 1560.