 Nicotiana goodspeedii. Photo: M. Fagg © ANBG |
 Nicotiana sauveolens. Photo: M. Fagg © ANBG |
 Nicotiana tabacum: reproduced from Engler & Prantl's Die Natürlichen Pflanzenfamilien IV 3b fig. 15 (1897). |
Taxonomy
Nicotiana L., Sp. Pl. 1: 180 (1753), Gen. Pl. 5th edn, 84 (1754); after Jean Nicot (1530–1600), consul from the King of France to Lisbon in 1560, who sent seeds of the tobacco plant to France.
Type species: N. tabacum L.
Annual or short-lived perennial herbs or spindly shrubs, glabrous or pubescent with glandular or non-glandular hairs. Leaves alternate, radical and/or cauline, simple, entire to sinuate, petiolate or sessile. Flowers solitary in leaf axils, or inflorescence panicle-like, rarely raceme-like with each flower subtended by a bract; flowers bisexual, actinomorphic or slightly zygomorphic, often both cleistogamous and chasmogamous. Calyx tubular to narrowly campanulate, the connate margins often thin and translucent (the thin areas termed `intersepalar membranes'), 5–lobed, persistent in fruit. Corolla tubular or salver-shaped, white, green, yellow or pink; limb 5–lobed, the lobes usually folded in bud. Stamens 5, equal or unequal in length, often 4 reaching throat of corolla-tube, the 5th shorter; anthers bilocular, dorsifixed, not cohering, dehiscing by longitudinal slits. Ovary bilocular; stigma capitate. Fruit a smooth-walled capsule surrounded by persistent calyx, dehiscing from apex by 4 (rarely 2) valves. Seeds reniform to C-shaped, often angled.
In native species, the limb of the corolla is usually closed in full sunlight and open in shade or after sunset. Cleistogamous flowers are found in some species, depending on the age of the plant, day length and temperature conditions; corollas of such flowers are usually very short, often scarcely exceeding the calyx. Keys and descriptions in this treatment are based on normal flowers only, and any measurements of corolla length need to be treated with caution.
A genus of 60–70 species, mostly native to South America but also found in North America, south-western Africa (1 species), Australia and the South Pacific region. Many species are important as drug plants, having a long history of use for smoking, chewing or snuff production in areas to which they are native or introduced. Commercial tobacco is mainly derived from N. tabacum L. and N. rustica L.
In Australia, 21 species endemic to the mainland and one introduced species (N. glauca Graham) widely naturalised. N. tabacum is cultivated commercially and is occasionally found as a spontaneous escape; N. alata Link & Otto and N. sylvestris Spegazzini & Comes are cultivated as garden ornamentals.
H. Wheeler, Studies in Nicotiana. II. A taxonomic survey of the Australian species, Univ. Calif. Publ. Bot. 18(4): 45–68 (1935); T.H. Goodspeed et al., The genus Nicotiana, Chron. Bot. 16: 1–536 (1954); N.T. Burbidge, The Australian species of Nicotiana L. (Solanaceae), Austral. J. Bot. 8: 342–380 (1960); P.K. Latz, The Central Australian species of Nicotiana, Austral. Pl. 7: 280–283 (1974); P. Horton, A taxonomic revision of Nicotiana (Solanaceae) in Australia, J. Adelaide Bot. Gard. 3: 1–56 (1981).
Changes since the Flora of Australia treatment
The number of endemic species has risen from 16 to 21 with the descriptions of N. burbidgeae, N. wuttkei, N. truncata and N. heterantha as new and the elevation of N. debneyi subsp. monoschizocarpa to species level (Symon & Lepschi 2007). There is possibly another native species to be described which is generally referred to as sp. Corunna, but it has not been treated here.
A revised sectional classification has been proposed in S. Knapp, M.W. Chase & J.J. Clarkson (2004). Nomenclatural changes and a new sectional classification in Nicotiana (Solanaceae). Taxon 53: 73-82. This sectional classification has not been used here.
A valuable summary of the cultural use of Nicotiana in Australia is provided in D.E.Symon (2005). Native tobaccos (Solanaceae:Nicotiana spp.) in Australia and their use by Aboriginal peoples. The Beagle 21: 1-10.
Fact sheets on the effects of ingestion of Nicotiana species on animals can be downloaded from the Australian Weeds and Livestock pages dealing with the effects of plants on various farm animals.
Further information about the toxic properties of Nicotiana species can be found with a search in the FDA Poisonous Plant Database
The composition of the scent of flowers of Nicotiana species has been the subject of some recent American work and the variation between species may have a phylogenetic origin while variation within a species has a number of possible origins and implications and is being investigated further (Raguso et al. 2003). Comparisons between hummingbird-pollinated diurnal species and moth-pollinated nocturnal species in America have shown that nectar traits can be influenced by the pollinator (Kaczorowski et al. 2005).
The phylogeny of Nicotiana has been investigated and it has been found to be sister to Tribe Anthocercideae e.g. Garcia & Olmstead (2003) and Clarkson et al (2004). The Australian native species all belong in sect. Suaveolentes Goodsp. together with a single African species from Namibia (N. africana Merxm.) and one from New Caledonia (N. fragrans Hooker) - see Knapp et al. (2004) or Clarkson et al. (2004).
Claire Marks of the Botany School at the University of Melbourne has been conducting studies on Nicotiana for some years for her Ph.D. - see Solanaceae conference abstract 2006, ASBS Newsletter 130: 4-6 and www.botany.unimelb.edu.au/botany/aboutus/contact/annual_report_2006.pdf and Marks (2010). Her results may well change some of the taxonomy reflected here.
References:
Clarkson, J.J., Knapp, S., Garcia, V.F., Olmstead, R.G., Leitch, A.R. & Chase, M.W. (2004). Phylogenetic relationships in Nicotiana (Solanaceae) inferred from multiple plastid DNA regions. Molecular Phylogenetics and Evolution 33: 75–90. http://depts.washington.edu/phylo/OlmsteadPubs/Clarkson.2004.MPE.pdf
Clarkson, J.J., Kelly, L.J., Leitch, A.R., Knapp, S. & Chase, M.W. (2010). Nuclear glutamine synthetase evolution in Nicotiana: Phylogenetics and the origins of allotetraploid and homoploid (diploid) hybrids. Molecular Phylogenetics and Evolution 55(1): 99-112.
Garcia, V.F. & Olmstead, R.G. (2003). Phylogenetics of Tribe Anthocercideae (Solanaceae) based on ndhF and trnL/F Sequence data. Systematic Botany 28: 609-615.
Kaczorowski, R.L., Gardener, M.C. & Holtsford, T.P. (2005). Nectar traits in Nicotiana sect. Alatae (Solanaceae) in relation to floral traits, pollinators and mating system. American J. Botany 92: 1270-1283.
Knapp, S., Chase, M.W. &
Marks, C.E. (2010). Definition of South Pacific taxa of Nicotiana section Sauveolentes (Solanaceae). Muelleria 28: 74-84.
Raguso RA, Schlumpberger BO, Kaczorowski RL, Holtsford TP. (2006) Phylogenetic fragrance patterns in Nicotiana sections Alatae and Suaveolentes. Phytochemistry 67 (17): 1931-1942. PDF
Raguso RA, Levin RA, Foose SE, Holmberg MW, McDade LA. (2003) Fragrance chemistry, nocturnal rhythms and pollination "syndromes" in Nicotiana. Phytochemistry 63(3): 265-84.
Symon D.E. & Lepschi B.J. 2007 A new status in Nicotiana (Solanaceae): N. monoschizocarpa (P.Horton) Symon & Lepschi. J. Adelaide Bot. Gard. 21. 92.
Thornburg R.W. 2007 Molecular biology of the Nicotiana floral nectary. In: Nicolson SW, Nepi M, Pacini E ed(s). Nectaries and nectar. Dordecht, The Netherlands: Springer 265-288. (n.v.).
Yoong Lim, K., Kovarik, A. Matyasek, R., Chase, MW., Clarkson, J.J., Grandbastien, M.A. & Leitch, A.R. (2007). Sequence of events leading to near-complete genome turnover in allopolyploid Nicotiana within five million years. New Phytologist 175(4): 756-763.
Key to species
Key adapted from P.Horton, A taxonomic revision of Nicotiana (Solanaceae) in Australia, J. Adelaide Bot. Gard. 3: 9–11 (1981). This key does not contain a number of later described species such as N. burbidgeae, N. truncata and N. wuttkei. These are treated in the interactive key available here.
1 Perennial, spindly shrub to 6 m; corolla yellow
Nicotiana glauca
1: Annual or short-lived perennial herb; corolla white or pink
2 Plant 1–3 m high; inflorescence short, dense, panicle-like; corolla white or pink
Nicotiana tabacum
2: Plant usually less than 1 m high; inflorescence loose, elongated, panicle- or raceme-like, or flowers solitary in leaf axils; corolla white
3 Ellipsoid-headed glandular hairs present at least on inflorescence
4 Lamina of lower leaves wider than long, or nearly as wide; cauline leaves petiolate
5 Petioles broadly winged; corolla-lobes obtuse
Nicotiana cavicola
5: Petioles very narrowly winged or almost terete; corolla-lobes acute
Nicotiana umbratica
4: Lamina of lower leaves longer than wide; at least the uppermost cauline leaves sessile or almost so
6 Inflorescence many-branched when mature, leafless; corolla-limb 6–13 mm diam., lobes obtuse to acute; seeds oblong to trapezoid
Nicotiana debneyi
6: Inflorescence few-branched when mature, often leafy in lower part; corolla-limb 10–25 mm diam., lobes notched; seeds reniform, acutely angled, C- or U-shaped
Nicotiana occidentalis
3: Ellipsoid-headed glandular hairs absent
7 Flowering stems leafy; flowers solitary in leaf axils or arising from internodes
Nicotiana benthamiana
7: Flowering stems leafless, or leafy at base only; flowers in raceme- or panicle-like inflorescences
8 Cauline leaves decurrent on stem
Nicotiana excelsior
8: Cauline leaves not decurrent on stem
9 Leaves mostly cauline, bases broadly auriculate and stem-clasping
10 Corolla-tube 15–20 mm long; capsule 5–9 mm long
Nicotiana amplexicaulis
10: Corolla-tube more than 25 mm long; capsule 7–16 mm long
11 Testa irregularly honeycombed or wrinkled; corolla-lobes usually obtuse
Nicotiana gossei
11: Testa regularly honeycombed; corolla-lobes usually notched
Nicotiana megalosiphon
9: Leaves radical and cauline or mostly radical; cauline leaves not broadly auriculate and stem clasping
12 Stems and leaves pubescent all over
13 Corolla-tube more than 25 mm long or, if shorter, the length more than 14 times the width (measured at top of calyx)
14 Corolla-tube usually less than 40 mm long; upper 4 anthers not all at the same level
Nicotiana simulans
14: Corolla-tube usually at least 40 mm long; upper 4 anthers all at the same level
Nicotiana megalosiphon
13: Corolla-tube less than 25 mm long or, if longer, the length less than 14 times the width (measured at top of calyx)
15 Pubescence velvety; intersepalar membranes inconspicuous; seeds C-shaped
Nicotiana velutina
15: Pubescence not velvety; intersepalar membranes often conspicuous; seeds reniform or acutely angled
16 Bases of stems usually white- or grey-woolly; hairs non-glandular
Nicotiana maritima
16: Bases of stems not white- or grey-woolly; hairs glandular and non-glandular
Nicotiana rotundifolia
12: Stems and leaves glabrous, glabrescent, or pubescent near base only
17 Capsule usually at least 3 times as long as wide; corolla-tube 1–2 mm wide at top of calyx, the length more than 14 times the width at that point
Nicotiana rosulata
17: Capsule not more than twice as long as wide; corolla-tube 1–6 mm wide at top of calyx, the length less than 14 times the width at that point
18 Stems and leaves glabrous or basal leaves, stem bases and young shoots pubescent
19 Corolla-tube usually more than 18 mm long, distinctly broadening up to the limb
Nicotiana suaveolens
19: Corolla-tube usually 8–18 mm long, not distinctly broadening up to the limb
Nicotiana goodspeedii
18: Stems and leaves glabrescent
20 Seeds C-shaped; intersepalar membranes inconspicuous
Nicotiana velutina
20: Seeds reniform or acutely angled; intersepalar membranes conspicuous
Nicotiana rotundifolia