Belongs within: Solanaceae.
Nicotiana, the tobaccos, is a genus of flowering plants, most diverse in the Americas, with funnel-shaped flowers borne in racemes or panicles (Hickman 1993). The leaves of several species, most notably N. tabacum, have a stimulant effect when smoked and they are widely cultivated for this purpose. Most species are herbs but tree tobacco N. glauca grows into a shrub or small tree up to six metres in height (Hickman 1993).
Characters (Hickman 1993): Annual to small tree. Leaves entire. Inflorescence a raceme or panicle, terminal. Flower with calyx five-lobed, more or less enlarging, not fully enclosing fruit; corolla generally radial, generally funnel-shaped to salverform; stamens 5, equal or one smaller. Fruit a capsule. Seeds many, minute, angled.
Nicotiana L. 1753L95 [incl. N. sect. Paniculatae Goodspeed 1945PSH82]
|--+--N. glutinosaOB08
| `--N. paniculataOB08 [=N. (sect. *Paniculatae) paniculataPSH82]
`--+--N. acuminataOB08
| |--N. a. var. acuminataH93
| `--N. a. var. multifloraH93
`--+--*N. tabacum Linnaeus 1753PSH82, OB08, CD07
|--N. africanaOB08
|--N. × flindersiensis Nicholls 1936 [N. glauca × N. suaveolens]PSH82
|--N. glauca Graham 1828OB08, PSH82
`--N. sect. Suaveolentes Goodspeed 1945PSH82
|--N. (sect. *S.) suaveolens Lehmann 1818PSH82, OB08, BR65 (see below for synonymy)
| |--N. s. var. suaveolensOB08
| `--N. s. var. excelsior Black 1915OB08, BR65 (see below for synonymy)
|--N. amplexicaulis Burb. 1960PSH82
|--N. benthamiana Domin 1929 [=N. suaveolens var. cordifolia Benth. 1868]PSH82
|--N. cavicola Burb. 1960PSH82
|--N. debneyi Domin 1929PSH82
| |--N. d. ssp. debneyiPSH82
| `--N. d. ssp. monoschizocarpa Horton 1981PSH82
|--N. goodspeedii Wheeler 1935PSH82
|--N. gossei Domin 1929PSH82
|--N. maritima Wheeler 1935PSH82
|--N. megalosiphon Van Heurck & Muell. Arg. in Van Heurck 1870 (see below for synonymy)PSH82
| |--N. m. ssp. megalosiphonPSH82
| `--N. m. ssp. sessilifolia Horton 1981PSH82
|--N. occidentalis Wheeler 1935PSH82
| |--N. o. ssp. occidentalisPSH82
| |--N. o. ssp. hesperis (Burb.) Horton 1981 [=N. hesperis Burb. 1960]PSH82
| `--N. o. ssp. obliqua Burb. 1960PSH82
|--N. rosulata (Moore) Domin 1929 (see below for synonymy)PSH82
| |--N. r. ssp. rosulataPSH82
| `--N. r. ssp. ingulba (Black) Horton 1981 [=N. ingulba Black 1933]PSH82
|--N. rotundifolia Lindley 1838PSH82 (see below for synonymy)
|--N. simulans Burb. 1960PSH82
|--N. umbratica Burb. 1960PSH82
`--N. velutina Wheeler 1935PSH82
Nicotiana incertae sedis:
N. acutifloraC06
N. alataD51
N. attenuataH93
N. auriculataC55
N. australasiaeC55
N. australis Br. in Comes 1899 (n. d.)PSH82
N. bonariensisD51
N. chinensis [incl. N. fruticosa]C55
N. clevelandiiH93
N. diglutaD37
N. langsdorfiiD51
N. obtusifolia [incl. N. trigonophylla]H93
N. persicaC55
N. plumbaginifoliaVB02
N. quadrivalvis [incl. N. bigelovii, N. bigelovii var. wallacei]H93
N. rusbyiD37
N. rusticaBR65
|--N. r. var. rusticaD51
|--N. r. var. humilisD51
`--N. r. var. texanaD51
N. sylvestrisD51
N. tomentosaD37
N. tomentosiformisGM96
Nicotiana megalosiphon Van Heurck & Muell. Arg. in Van Heurck 1870 [incl. N. suaveolens var. longiflora Benth. 1868]PSH82
Nicotiana rosulata (Moore) Domin 1929 [=N. suaveolens var. rosulata Moore 1899; incl. N. stenocarpa Wheeler 1960]PSH82
Nicotiana rotundifolia Lindley 1838PSH82 [=N. suaveolens var. rotundifolia (Lindley) Comes 1899PSH82; incl. N. rotundifolia ssp. aridicola Burb. 1960PSH82, N. fastigiata Nees 1844BR65, N. neesii Lehm. ex Nees in Leh. 1960PSH82]
Nicotiana suaveolens Lehmann 1818PSH82, OB08, BR65 [=N. undulata Vent. 1803 non Ruíz Lopez & Pavón 1799PSH82, N. suaveolens var. undulata Comes 1899PSH82; incl. N. exigua Wheeler 1981PSH82, N. suaveolens var. parviflora Benth. 1868PSH82]
Nicotiana suaveolens var. excelsior Black 1915OB08, BR65 [=N. excelsior (Black) Black 1926PSH82; incl. N. macrocalyx Domin 1929BR65]
*Type species of generic name indicated
References
[BR65] Black, J. M., & E. L. Robertson. 1965. Flora of South Australia. Part IV. Oleaceae–Compositae. W. L. Hawes, Government Printer: Adelaide.
[C55] Candolle, A. de. 1855. Géographie Botanique Raisonée: Ou exposition des faits principaux et des lois concernant la distribution géographique des plantes de l’époque actuelle vol. 2. Librairie de Victor Masson: Paris.
[CD07] Cantino, P. D., J. A. Doyle, S. W. Graham, W. S. Judd, R. G. Olmstead, D. E. Soltis, P. S. Soltis & M. J. Donoghue. 2007. Towards a phylogenetic nomenclature of Tracheophyta. Taxon 56 (3): E1–E44.
[C06] Cheeseman, T. F. 1906. Manual of the New Zealand Flora. John Mackay, Government Printer: Wellington.
[D37] Dobzhansky, T. 1937. Genetics and the Origin of Species. Columbia University Press: New York.
[D51] Dobzhansky, T. 1951. Genetics and the Origin of Species 3rd ed. Columbia University Press: New York.
[GM96] Griffiths, A. J. F., J. H. Miller, D. T. Suzuki, R. C. Lewontin & W. M. Gelbart. 1996. An Introduction to Genetic Analysis 6th ed. W. H. Freeman and Company: New York.
[H93] Hickman, J. C. (ed.) 1993. The Jepson Manual: Higher Plants of California. University of California Press: Berkeley (California).
[L95] Liogier, H. A. 1995. Descriptive Flora of Puerto Rico and Adjacent Islands: Spermatophyta-Dicotyledoneae vol. 4. Melastomataceae to Lentibulariaceae. Editorial de la Universidad de Puerto Rico.
[OB08] Olmstead, R. G., L. Bohs, H. A. Migid, E. Santiago-Valentin, V. F. Garcia & S. M. Collier. 2008. A molecular phylogeny of the Solanaceae. Taxon 57 (4): 1159–1181.
[PSH82] Purdie, R. W., D. E. Symon & L. Haegi. 1982. Solanaceae. Flora of Australia 29: 1–197.
[VB02] Vijay, S. K., & T. N. Bhardwaja. 2002. Vegetation and phenodynamics of wetlands of central Rajasthan. Journal of the Bombay Natural History Society 99 (3): 573–581.