Datura is a genus of highly poisonous, vespertine-flowering plants in the nightshade family (Solanaceae), order Solanales. Authorities recognise between nine and fourteen species, depending on how broadly species boundaries are drawn — taxonomic complexity within the genus is considerable, as populations show extreme variability in plant size, leaf dimensions, and flower size depending on local conditions, and many nominally "new species" have later been reduced to varieties or subspecies.
Plants are herbaceous annuals or short-lived perennials, typically reaching up to 2 metres in height. Leaves are alternate, 10–20 cm long, with lobed or toothed margins. The flowers are among the most distinctive features of the genus: erect (not pendulous), trumpet-shaped, 5–20 cm long, ranging in colour from white to yellow and pale purple, and opening primarily at dusk — hence the term vespertine. The fruit is a spiny, dehiscent capsule that splits open at maturity to release numerous seeds, which disperse readily into pastures, fields, and disturbed ground.
All parts of all Datura species are toxic. The plants contain tropane alkaloids, principally scopolamine and atropine, concentrated especially in the seeds and flowers. These alkaloids cause anticholinergic toxidrome — historically summarised in the mnemonic "blind as a bat, mad as a hatter, red as a beet, hot as a hare, dry as a bone" — and in sufficient doses cause respiratory depression, arrhythmias, delirium, hallucinations, and death. Because of this toxicity, Datura holds a prominent place in ethnobotany: it was used in witches' preparations alongside deadly nightshade, henbane, and mandrake in European tradition, and certain species have been used ritualistically as entheogens by Native American groups.
Mexico is considered the centre of origin of the genus, with most species native to dry, temperate, and subtropical regions of the Americas. A small number of species — notably D. ferox (China), D. metel (India and Southeast Asia), and D. leichhardtii (Australia) — were previously thought to have extra-American native ranges, but current evidence strongly suggests they are post-Columbian introductions. Datura is closely related to Brugmansia (the angel's trumpets), which was formerly included in Datura but is now placed in its own genus on the basis of its woody habit and indehiscent fruits. Both genera belong to the solanaceous tribe Datureae, which also includes the recently described monotypic genus Trompettia.
Etymology
The generic name Datura derives from Hindi धतूरा (dhatūra, "thorn-apple"), itself from Sanskrit धत्तूर (dhattūra, "white thorn-apple"), originally referring to Datura metel of Asia. The English colloquial name "jimsonweed" is a contraction of "Jamestown-Weed," recorded by the Virginia colonist Robert Beverley in reference to the plant's prevalence around Jamestown. In Mexico the common name toloache comes from the Nahuatl tolohuaxihuitl, meaning "the plant with the nodding head," alluding to the drooping seed capsules of section Dutra.
Distribution
Most Datura species are native to Mexico, which is regarded as the centre of origin of the genus, with the remaining species distributed across dry, temperate, and subtropical regions of the Americas. D. stramonium is now naturalised across Europe, Asia, and beyond. Species previously considered native to China (D. ferox), India and Southeast Asia (D. metel), and Australia (D. leichhardtii) are now regarded as almost certainly post-Columbian introductions to those regions.
Ecology
Datura grows in disturbed, dry, and often nutrient-poor soils — pastures, roadsides, fields, and wasteland. Plants reseed freely and can become invasive where conditions are favourable. Their large, pale, night-opening flowers attract nocturnal pollinators. The larvae of some Lepidoptera species, including Hypercompe indecisa, feed on Datura foliage, while most larger herbivores, including cattle, typically avoid consuming the plants. Datura nectar collected by certain wasps (e.g., Brachygastra lecheguana) can render their honey toxic during the blooming season.
Cultivation
Datura is usually grown as an annual, raised from the seed produced in its spiny capsules. Some tuberous-rooted perennial species can be overwintered with care. Plants require warm, sunny positions and well-drained soil that keeps the roots relatively dry; they are susceptible to root fungi and should not be given anaerobically composted organic matter or fresh manure. Grown in good outdoor positions they tend to reseed and may become invasive. In containers, porous and well-aerated potting mix with adequate drainage is essential.
Cultural Uses
Datura has a documented history of use as a poison, hallucinogen, and ritual plant across multiple cultures. In European tradition it was a classic ingredient in "witches' brews" alongside deadly nightshade, henbane, and mandrake. Certain Native American groups have used it ritualistically as an entheogen. In India, D. metel has been used in Ayurvedic medicine since ancient times and is offered to the deity Shiva; it also features in Ganesh Chaturthi. In South Asia and parts of Europe, Datura was historically used as a poison for murder and suicide. The alkaloids scopolamine and atropine extracted from Datura have legitimate medical applications recognised in both New and Old World traditions.
Taxonomy Notes
Classifying Datura to species level is difficult because of extreme intraspecific variability and overlapping morphological traits between species. Specialists Ulrike and Hans-Georg Preissel recognise nine species, while Kew's Plants of the World Online lists fourteen. Many names described as new species have subsequently been reduced to varieties. A group of South American arborescent species formerly placed in Datura are now placed in the distinct genus Brugmansia, separated on the basis of woody habit and indehiscent fruits. The tribe Datureae, to which Datura belongs, has recently been expanded to include the newly described monotypic genus Trompettia, whose sole species (Trompettia cardenasiana) was previously misclassified in Iochroma. The American Brugmansia and Datura Society (ABADS) has been the official International Cultivar Registration Authority for Datura since 2002.
