Tobacco

In order to prevent their leaves being eaten by insects, the shrubs and herbs that make up the genus Nicotiana, to which the tobacco plant belongs, produce an extraordinary cocktail of chemicals. On average 10 percent of the plants' metabolic effort is spent producing just the alkaloids that go into the mix. The flow of chemicals to the glands of some American species is so copious that it literally drowns the insects attempting to make a meal of it. Such devotion of its metabolic efforts indicates the plant faces formidable enemies in nature, and tobacco eating insects are a resilient lot. Indeed, the newly hatched larvae of the tobacco grub recoil at their first bite of a tobacco leaf, but soon reconcile themselves to their toxic food and will thereafter take no other.

South America is the principal home of the tobacco genus [properly the genus Nicotiana], but some members are flung as far and wide as southern Africa and Australia, suggesting that the lineage may be a venerable one which evolved at a time when these landmasses were joined [Gondwanaland]. The North American species probably travelled north with the glyptodonts and sloths after the formation of the Panamanian land bridge. People, like tobacco grubs, acquired a taste for the toxic chemicals, and it was from among these immigrant species that North American Indians first selected plants that offered a good smoke. By AD 500 the Maya were already in the habit, and by the seventeenth century smoking had spread through vast areas of the continent.

Curiously, the tobacco enjoyed by Sir Walter Raleigh and first grown in Virginia in 1612 is not the species cultivated for smoking today. Raleigh relished the aroma of Nicotiana paniculata [This seems to be a very salt tolerant species it appears that makes sense in the Tidewater], which, although it is no longer smoked, has not vanished entirely as a crop-it is still grown in Eurasia as a source of insecticides. [Interestingly enough this does not even seem to be the same species that John Rolfe replaced when he reformed tobacco planting in Virginia, as Nicotiana rustica is usually the plant credited with being too strong. N. rustica has some reputation of being a hallucinigen and being used in Native American mgic and religion, it is fact a Chilean Mapuche import, and it makes sense that it might have introdued by the settlers, just as its successor was introduced from Barbados.] The plant that fills the fields of the American South today is Nicotiana tabacum, which appears to be a hybrid species with Argentinian and Bolivian ancestry.

From The Eternal Frontier. by Tim Flannery (William Heinemann: London, 2001) pp. 277-8

I have always read that Indian tobacco as smoken by Medicine men and shamans was not the same stuff we smoke today, this seems to shed a little light on the subject. The question the becomes, where do I find some Nicotiana rustica to try smokin?