4. Species

Smoking tobacco
Common smoking tobacco and the general tobacco of world commerce is exclusively Nicotiana tabacum, which originated along the eastern slopes of the Andes mountains, and spread into all of South America and the Caribbean. Different varieties of N. tabacum are now successfully grown throughout the world, including Nepal, Scandinavia, the Alps, and on every continent except Antarctica. With the ability to start seed indoors, and then transplant outdoors after about 8 weeks, and to cure green-harvested tobacco indoors as well, tobacco can be successfully grown in any location that experiences a vegetable growing season of at least 70 to 80 days. Shorter season varieties also exist.

Rustica
The cultivated, Native American tobacco of the regions stretching from Mexico north-eastward, into the Mississippi valley, and as far as southeastern and south-central Canada was Nicotiana rustica. N. Rustica will propagate itself to a very limited extent, but it is not wild, and will not persist after more than a few years. Its millennia of intentional, human cultivation and selection limited its ability to adequately disperse its own seed spontaneously, though it does so more efficiently than N. tabacum.

Wild tobacco species
In the upper mid-west of the US, the west coast, and up into western Canada, several other species were used and sometimes traded, but these were and continue to be wild species (e.g. N. quadrivalvis, N. bigelovii, N. attenuata) that generally propagate themselves without human intervention−though they were sometimes intentionally cultivated. Blending with a portion of N. Rustica is used today in cigarette manufacture in some countries in Eastern Europe and elsewhere, to increase nicotine concentrations. Continued consumption of wild species is generally limited to ceremonial uses.

North American Nicotiana species