2. Nicotiana rustica L. (wild tobacco)

Pl. 562 f–h; Map 2619

Plants annual, taprooted. Stems 40–150 cm long, relatively stout, densely pubescent with short, often woolly or matted, multicellular, mostly gland-tipped hairs, scattered, longer spreading hairs sometimes also present. Leaves relatively numerous above the usually nonpersistent basal rosettes and only gradually reduced toward the stem tip (the stems appearing relatively densely leafy), the lower leaves moderately petiolate, the upper leaves short-petiolate. Leaf blades 6–15(–30) cm long, those of the lower leaves broadly ovate to nearly heart-shaped, rounded to bluntly pointed at the tip, rounded to truncate or shallowly cordate at the often oblique base; those of the upper leaves ovate to elliptic, angled or slightly tapered to a bluntly or sharply pointed tip; the margins entire to slightly wavy, relatively flat, the surfaces sparsely to moderately pubescent with short, mostly gland-tipped hairs, more densely so along the veins, often also with sessile glands. Inflorescences elongate to somewhat pyramidal panicles, mostly with numerous flowers. Calyces 8–15 mm long, faintly 5- or 10-ribbed, glandular-hairy, the tube longer than the 5, ovate to broadly ovate-triangular lobes, these angled or curved to mostly bluntly pointed tips. Corollas 1.5–2.0 cm long, glandular-hairy, lemon yellow to greenish yellow, the tube relatively broad, narrowly funnelform to nearly tubular but usually slightly constricted at the tip, the lobes 2.5–4.0 mm long, more or less semicircular or the margin appearing merely scalloped. Fruits 7–16 mm long, broadly oblong-ovoid to nearly globose. Seeds 0.7–1.1 mm in longest dimension, the surface with a network of ridges, brown to dark brown. 2n=48. July–October.

Introduced, uncommon, known thus far only from a single historical collection from the city of St. Louis (native of South America, introduced sporadically in mostly the northeastern U.S.; Canada). Habitat unknown, but presumably open, disturbed areas.

Even in pre-Columbian times, Native Americans cultivated N. rustica for medicinal use and to smoke as a tobacco (Steyermark, 1963; Epstein, 1981; Moerman, 1998). In more recent years, with increased reliance on commercially available N. tabacum, cultivation of the species has declined sharply and it does not appear as an escape any longer. Heiser (1969) noted that although this species had a South American origin similar to that of N. tabacum, it apparently was not smoked in South America. Its mode of arrival in North America is not well understood.