Tree tobacco

Small trees or shrubs. Stems usually branched near base, occasionally with distinct trunk (branches drooping), 10–60(–100) dm, glabrous, somewhat glaucous. Cauline leaves: peti­ole length 1/2 blade (not winged); blade ovate to lanceolate, 5–25 cm, base acute or cordate, apex rounded, (rubbery), surfaces glabrous, glaucous. Inflorescences branched, not leafy; flowering diurnal. Pedicels 0.3–1 cm. Flowers: calyx green, (evenly cylindric), 1–1.5 cm, without membranous sinuses, glabrous or minutely pubescent, lobes sharply triangular, equal, much shorter than tube; corolla straight, 2.5–4.5 cm (excluding limb), glabrous or finely pubescent externally, tube bright yellow to greenish yellow, (cylin­dric to clavate, slightly constricted apically), 0.5–0.8 cm × 3 mm, widening slightly to throat 1.5–4 cm × 6–8 mm, glabrous within, limb assurgent, greenish yellow or bright green (usually distinct color from tube in young flowers), turning yellow and same color as tube with age, circular or pentagonal, 0.6–0.8 cm diam., lobes rounded, broadly triangular, equal; stamens inserted at base of throat, extending to corolla mouth; filaments subequal 2.5–4.5 cm, (geniculate at base), glabrous; style straight, exceeding stamens and exserted from corolla mouth. Capsules ovoid, 0.7–1.5 cm. Fruiting calyces not tearing along sinuses, covering mature cap­sule. Seeds 0.5 mm. 2n = 24.

Flowering year-round. Open areas along roads, dis­turbed habitats, often in Mediterranean vegetation; 0–2600 m; introduced; Ala., Ariz., Calif., Fla., Ga., Miss., Nev., N.Mex., Tex.; South America (Argentina, Bolivia, Chile); introduced also in Mexico, Europe (France, Greece, Italy, Spain, Turkey), sw Asia (Israel, Lebanon), Africa, Pacific Islands (New Zealand), Australia.

Nicotiana glauca is registered as an invasive plant in the United States (www.invasives.org). It can form mono­dominant stands due to high seed set and ger­mination success. It was originally introduced from Argentina to Mexico, thence to the United States and worldwide (T. H. Goodspeed 1954). Siphaulax glabra Rafinesque is an illegitimate, superfluous name for this species.