This section is from the book "Handbook Of Hardy Trees, Shrubs, And Herbaceous Plants", by W. Botting Hemsley. Also available from Amazon: Handbook of hardy trees, shrubs, and herbaceous plants.
Tall stout usually viscid large-leaved herbs. Flowers racemose or paniculate. Calyx campanulate, 5-lobed. Corolla funnel- or salver-shaped; limb plaited. Stamens included. Fruit a 2-celled many-seeded capsule, dehiscing at the top in 2 or 4 valves. The species are natives of tropical America and Eastern Asia, but several are now found in a semi-wild state all over the world. The genus was named after Nicot, a Portuguese, who it is believed introduced tobacco into France. These plants are seldom used for ornamental purposes, though some of them might be worthy of a place in large gardens on account of their ample foliage.
N. rustica, N. Tabacum, and N. macrophylla, syn. N, latis-sima, are the species of Tobacco commonly grown in Europe and elsewhere for their leaves. The first has yellowish green flowers and is of dwarfish habit, the others have pink flowers and large simple decur-rent leaves, auricled at the base in the latter.
N. wigandioides and N. glauca are ornamental in foliage, but the flowers are small and insignificant.