Datura L.

Solanaceae, Jennifer M Edmonds. Oliganthes, Melongena & Monodolichopus, Maria S. Vorontsova & Sandra Knapp. Flora of Tropical East Africa. 2012

Morphology General Habit

Annual or semiperennial herbs and shrubs, often malodorous.

Morphology Stem

Main stem often stout, woody and dichotomously branched, spherical stalked brownish glands present on all parts

Morphology Leaves

Leaves alternate or opposite

Morphology Reproductive morphology Flowers

Flowers usually solitary and in branch forks, always erect, usually fragrant, opening diurnally and remaining open during anthesis, with prominent venation; pedicels short, elongating during fruiting

Morphology Reproductive morphology Flowers Calyx

Calyx tubular, usually enclosing the lower half of the corolla tube; calyx lobes five; base circumsessile, forming a ridged collar which often persistent

Morphology Reproductive morphology Flowers Corolla

Corolla tubular below becoming funnel- or trumpet-shaped above, sometimes double or triple; tube long and slender, the lobes fused almost to the apex, with 5 or 10 terminal acuminate to caudate lobes or teeth

Morphology Reproductive morphology Flowers Androecium Stamens

Stamens inserted on lower half of corolla tube and alternating with lobes, equal, included; filaments glabrous above, slender, filiform, widening towards point of adnation to corolla tube from where usually sparsely pilose; anthers oblong, basifixed, free, dehiscing longitudinally, often with long hairs on dehiscent margins

Morphology Reproductive morphology Flowers Gynoecium Ovary

Ovary superior, conical, softly spinose or tuberculate, bilocular above, but 4-loculate basally owing to a false septum, ovules numerous, placentation axile; style long, filiform, glabrous, sometimes exserted beyond anthers but included; stigma bilobed, clasping the stylar apex

Morphology Reproductive morphology Fruits

Fruit ovoid or globose 2–4celled capsules, dehiscing irregularly or by 2 or 4 valves from the apex; valves usually spinose or tuberculate, rarely smooth, subtended by the persistent discoid remains of the calyx which adherent or reflexed, forming a frill or collar beneath capsule; fruiting pedicels elongated and stout, erect or pendulous

Morphology Reproductive morphology Seeds

Seeds large, reniform or discoid, with a thick (suberose) corky testa; funicular caruncle (elaiosome) welldeveloped, numerous.

Note

All Old World Daturas, collectively known as the Thorn Apples, were introduced from the Americas during the early years of intensive European colonization of the New World ( cf. Symon & Haegi, 1991 in Solanaceae III: 197; Persson et al., 1999). Three naturalised species are found throughout the East African region, where they are probably also widely cultivated for their hallucinogenic, medicinal and narcotic effects as well as for their ornamental value. They all contain the tropane alkaloids scopolamine and hyoscyamine, plus steroidal lactones of the withanoloid group ( cf. Hunziker, 2001 for extensive references).

Flora Zambesiaca. Vol. 8, Part 4. Solanaceae. Gonçalves AE. 2005

Morphology General Habit

Annual or short-lived perennial herbs or sometimes subshrubs or shrubs from a woody rootstock, often foetid, glabrous or pubescent to glabrescent; indumentum of erect to appressed, simple non-glandular to glandular trichomes, dense on immature foliage, pedicels and calyces, sparse or absent on mature parts, or sometimes remaining pubescent Annual or short-lived perennial herbs or sometimes subshrubs or shrubs from a woody rootstock, often foetid, glabrous or pubescent to glabrescent; indumentum of erect to appressed, simple non-glandular to glandular trichomes, dense on immature foliage, pedicels and calyces, sparse or absent on mature parts, or sometimes remaining pubescent.

Morphology Leaves

Leaves alternate, the upper ones in the floral region sometimes in pairs appearing opposite with one larger than the other, petiolate, entire or deeply or shallowly sinuate-dentate or coarsely and sharply incised-dentate Leaves alternate, the upper ones in the floral region sometimes in pairs appearing opposite with one larger than the other, petiolate, entire or deeply or shallowly sinuate-dentate or coarsely and sharply incised-dentate.

Morphology Reproductive morphology Flowers

Flowers usually solitary, axillary or in the forks of the branching stem, actinomorphic or almost so. Flowers usually solitary, axillary or in the forks of the branching stem, actinomorphic or almost so; pedicels ± erect but sometimes becoming pendulous in fruit.

Morphology Reproductive morphology Flowers Pedicel

Pedicels ± erect but sometimes becoming pendulous in fruit

Morphology Reproductive morphology Flowers Calyx

Calyx shorter than the corolla tube, tubular, usually 5-angled to 5-ribbed, somewhat inflated or appressed to the corolla tube, 5-lobed or narrowly toothed; tube circumscissile near the base after anthesis, leaving an annular basal remnant which in fruit is often enlarged into a spreading or reflexed shield or cup; lobes much shorter than the tube, with valvate aestivation Calyx shorter than the corolla tube, tubular, usually 5-angled to 5-ribbed, somewhat inflated or appressed to the corolla tube, 5-lobed or narrowly toothed; tube circumscissile near the base after anthesis, leaving an annular basal remnant which in fruit is often enlarged into a spreading or reflexed shield or cup; lobes much shorter than the tube, with valvate aestivation.

Morphology Reproductive morphology Flowers Corolla

Corolla white or violet to purplish, infundibuliform to ± tubular, sometimes double or triple; tube long and narrow widening towards the throat; limb broad, plicate, spreading, 5(6)-lobed, or 10(12)-lobed when a secondary lobe appears between the main lobes; lobes short and cuspidate or sometimes long-caudate, with a conduplicate-contorted aestivation Corolla white or violet to purplish, infundibuliform to ± tubular, sometimes double or triple; tube long and narrow widening towards the throat; limb broad, plicate, spreading, 5(6)-lobed, or 10(12)-lobed when a secondary lobe appears between the main lobes; lobes short and cuspidate or sometimes long-caudate, with a conduplicate-contorted aestivation.

Morphology Reproductive morphology Flowers Androecium Stamens

Stamens (4)5(6), ± equal, included or slightly exserted; filaments linear-subulate, adnate to the lower half of the corolla tube; anthers basifixed, linear-oblong to narrowly elliptic or ovate in outline, slightly curved, dehiscing by longitudinal slits Stamens (4)5(6), ± equal, included or slightly exserted; filaments linear-subulate, adnate to the lower half of the corolla tube; anthers basifixed, linear-oblong to narrowly elliptic or ovate in outline, slightly curved, dehiscing by longitudinal slits.

Morphology Reproductive morphology Flowers Disc

Disk none Disk none.

Morphology Reproductive morphology Flowers Gynoecium Ovary

Ovary ± globose, provided with soft excrescences (rarely smooth), 2-locular, sometimes with a false septum and 4-locular below; ovules numerous in each locule on placentas adnate to the septa, hemicampylotropous.

Morphology Reproductive morphology Flowers Gynoecium Style

Style slender.

Morphology Reproductive morphology Flowers Gynoecium Stigma

Stigma often 2-lobed to 2-lamellate at the tip, included

Note

All parts of the plants are extremely toxic. Flour made from grain containing datura seed has caused poisoning and stock poisoning can occur when datura plants are gathered together with fodder plants. Satina & Avery in Chron. Bot. 20: 36 (1959) considered Datura sensu lato to include Brugmansia, however, recent workers treat these as distinct and I follow D'Arcy in Ann. Missouri Bot. Gard. 60: 582 (1974) in keeping the genera separate. Two sections are recognized: sect. Datura (sect. Stramonium Bernhardi) with D. stramonium and D. ferox and sect. Dutra Bernhardi with D. inoxia and D. metel.

Morphology Reproductive morphology Flowers Gynoecium Pistil

Ovary ± globose, provided with soft excrescences (rarely smooth), 2-locular, sometimes with a false septum and 4-locular below; ovules numerous in each locule on placentas adnate to the septa, hemicampylotropous; style slender; stigma often 2-lobed to 2-lamellate at the tip, included.

Morphology Reproductive morphology Fruits

Fruit a capsule, globose to ellipsoid or ovoid, erect or deflexed, leathery, covered with soft or woody spine-like excrescences or tubercles (rarely smooth), semi-4-locular, apically dehiscent by 2 loculicidal and sometimes also 2 septicidal slits to ± halfway, the 4 dry valves incomplete. Fruit a capsule, globose to ellipsoid or ovoid, erect or deflexed, leathery, covered with soft or woody spine-like excrescences or tubercles (rarely smooth), semi-4-locular, apically dehiscent by 2 loculicidal and sometimes also 2 septicidal slits to ± halfway, the 4 dry valves incomplete

Morphology Reproductive morphology Seeds

Seeds numerous, relatively large, laterally compressed, wedge-shaped or reniform, or ± oblong in outline, sometimes with a funicular caruncle (elaiosome); testa moderately crustaceous, hard, or moderately subereous, very thick, smooth or roughened; embryo ± circinnate, flattened, subperipheral, in the fleshy or horny endosperm, with radicle terete; cotyledons semi-terete or linear in outline. Seeds numerous, relatively large, laterally compressed, wedge-shaped or reniform, or ± oblong in outline, sometimes with a funicular caruncle (elaiosome); testa moderately crustaceous, hard, or moderately subereous, very thick, smooth or roughened; embryo ± circinnate, flattened, subperipheral, in the fleshy or horny endosperm, with radicle terete; cotyledons semi-terete or linear in outline