Datura L.
Datura is a small New World genus of probably not more than eight or ten species. In a recent synopsis Dupin & Smith (2018) recognize 12 species. Most are native in the southern United States and Mexico. Several species are widely cultivated as ornamentals (see Shaw 2000) or have become notorious agricultural or environmental weeds.
The exact origin of the genus Datura long remained uncertain. Datura stramonium is often told to be native in parts of Europe and D. ferox is a native of eastern Asia according to many authors (see for instance Moore 1972, Haegi 1976, Clement & Foster 1994). However, Symon & Haegi (1991) suggest a New World origin for the entire genus.
Dupin & Smith (2018) present a key for the identification of all Datureae worldwide (Datura, Brugmansia and Trompettia).
1. Capsule deflexed, globose, irregularly dehiscent at maturity. Corolla 11-19 cm long. Plant densely glandular-hairy === 2. Datura innoxia
1. Capsule erect, oblong, regularly dehiscent at maturity. Corolla 4-10 cm long. Plant (sub-) glabrous or sometimes slightly pubescent (but never glandular === 2
2. Capsule with few, unequal, stout spines that are 10-30 mm long. Corolla 4-6 cm long, always white === 1. D. ferox
2. Capsule with numerous, more or less equal spines that are up to 15 mm long. Corolla 5-10 cm long, white or purplish === 3. D. stramonium
Literature:
Avery A.G., Satina S. & Rietsema J. (1959) Blakeslee: the genus Datura. The Ronald Press Company, New York: 289 p.
Barclay A.S. (1959) New considerations in an old genus: Datura. Bot. Mus. Leafl. Harvard 18: 245-272. [available online at: https://archive.org/details/cbarchive_40559_newconsiderationsinanoldgenu...
Bye R. & Sosa V. (2013) Molecular Phylogeny of the Jimsonweed Genus Datura (Solanaceae). Systematic Botany 38(3): 818-829. [available online at: http://www.bioone.org/doi/pdf/10.1600/036364413X670278]
Child A. & Shaw J.M.H. (1999) Keys to Datura and Brugmansia (Solanaceae). BSBI News 82: 54-57.
Clement E.J. & Foster M.C. (1994) Alien plants of the British Isles. BSBI, London: XVIII + 590 p.
De Wolf G.P. (1956) Notes on cultivated Solanaceae. 2. Datura. Baileya 4: 13-23.
Dupin J. & Smith S.D. (2018) Phylogenetics of Datureae (Solanaceae), including description of the new genus Trompettia and re-circumscription of the tribe. Taxon 67: 359-375.
Haegi L. (1976) Taxonomic account of Datura L. in Australia with a note on Brugmansia Pers. Austr. J. Bot. 24: 415-435. [available online at: http://www.publish.csiro.au/?act=view_file&file_id=BT9760415.pdf]
Hammer K., Romeike A. & Tittel C. (1983) Vorarbeiten zur monographischen Darstellung von Wildpflanzensortimenten: Datura L., sectiones Dutra Bernh., Ceratocaulis Bernh. et Datura. Kulturpflanze 31: 13-75.
Jäger E.J., Ebel F., Hanelt P. & Müller G. (eds.) (2008) Rothmaler Band 5. Exkursionsflora von Deutschland. Krautige Zier- und Nutzpflanzen. Springer Verlag, Berlin: 880 p.
Moore D.M. (1972) Datura. In: Tutin T.G. & al. (eds.), Flora Europaea, vol. 3. Cambridge University Press, Cambridge: 200-201.
Preissel U. & Preissel H.G. (2001) Brugmansia and Datura: angel's trumpets and thorn apples (rev.ed.). Auckland, New Zealand. David Bateman Ltd.: 144p.
Shaw J.M.H. (2000) Datura. In: Cullen J. & al. (eds.), The European Garden Flora, vol. 6. Cambridge University Press, Cambridge: 247-248.
Symon D.E. & Haegi L.A.R. (1991) Datura (Solanaceae) is a New World genus. In: Hawkes & al. (eds.), Solanaceae III: Taxonomy, chemistry, evolution. Royal Botanic Gardens, Kew: 197-210.
Van Ooststroom S.J. & Reichgelt Th.J. (1966) Solanaceae-Orobanchaceae. In: van Ooststroom S.J. & Van der Veen R. a.o. (eds.), Flora Neerlandica, vol. 4(2). KNBV, Amsterdam: 65 p.