Nicotiana angustifolia Miller; N. fruticosa Linnaeus

Herbs, perennial, or shrubs to small trees, soft-wooded, without basal rosette. Stems single, usually unbranched, woody at base (hollow), 10–30 dm, viscid-pubescent. Cauline leaves sessile; blade elliptic to lanceolate, 5–50 cm, becoming smaller distally, base tapering or decurrent, apex acute to acuminate, surfaces viscid-pubescent. Inflorescences branched with distinct central axis (branches themselves branched and shorter than central axis), usually somewhat leafy; flowering diurnal. Pedicels (spreading), 0.5–1.5 cm. Flowers: calyx uniformly green, 1.2–2.5 cm, viscid-pubescent, lobes long-triangular, equaling or shorter than tube, unequal; corolla straight or strongly curved in distal 1/2, 3–5 cm (excluding limb), viscid-puberulent externally, tube pale greenish cream to pink or red, slightly curved or straight, 0.7–1.5 cm × 2–2.5 mm, widening to throat 25–40 × 5 mm, somewhat dilated distally, glabrous or minutely puberulent internally, limb spreading to somewhat reflexed, pale pink to reddish pink, occasionally white, pentagonal, 2–3 cm diam., lobes pale pink to reddish pink, occasionally white, acute; stamens inserted near base of throat; filaments unequal, 4 slightly exserted, 3–5 cm, 1 included, 3 cm (shorter than the other 4), pubescent on proximal 1/2; style straight or slightly curved, ± equaling longer stamens. Capsules narrowly ellipsoid, ovoid, or globose, 1.2–2 cm. Fruiting calyces often tearing at sinuses (especially in cultivars), covering 1/2 mature capsule. Seeds 0.5 mm. 2n = 48.

Flowering year-round. Disturbed areas, field edges; 0–1000 m; introduced; Ont.; Fla., Ga., Ky., La., Md., Mich., Mo., N.C., S.C., Tenn., Va., W.Va.; South America; cultivated nearly worldwide except Antarctica.

Nicotiana tabacum is the principal tobacco of commerce and was the mainstay of the economy of the Chesapeake Bay region during Colonial times. It replaced N. rustica as the main cultivated species in North America in the early 1600s. Most herbarium specimens of N. tabacum come from gardens or research greenhouses, but it occasionally escapes and is an ephemeral weed where the climate is mild. Commercial tobacco cultivars are grown for their large leaves, and flowers are removed to allow further growth of top leaves before harvest, but if marginal individuals are not harvested and are collected, they could be mistaken for naturalized weeds. Nicotiana tabacum is widely cultivated across North America.