Plants dichotomously branching annual herbs, to 40+ cm tall; young branches usually villous, glabrescent with age. Leaves alternate, petiolate; petioles up to 8 cm long, villous; blades ovate, up to 11 cm long, width usually 1/2-2/3rds length, surfaces variously strigose except the midveins villous, bases unequal, margins irregularly lobate or sinuate-dentate, tips acute. Flowers axillary, pedicillate, erect; pedicels 0.7-1.8 cm long at anthesis, becoming elongating to 1.5-cm long and reflexed in fruit; calyces cylindrical, 2.4-4.6 cm long, sparsely pubescent, 5-toothed, teeth 3-5 mm long, bases 3-5 mm wide, cirumscissile in fruit; corollas funnel-shaped, 6-7.5 cm long, white, plicate, with 5 sets of 3-veins, each set terminating in a tooth, corolla margins bisinuate between the teeth, forming an obtuse lobule between each pair of teeth making the corolla appear 10-angled; stamens 5, epipetalous attached to the corolla tube about 2.5-3 cm from the base; filaments glabrous, 2-2.3 cm long; styles 4.6-5.7 cm long, equalling or slightly exceeding the anthers; ovaries covered with spinelike hairs. Fruits subtended by the disk-like remnants of the calyces, pendent, 2-3.5 cm long, irregularly dehiscent, covered with semicapillaceous pubescent bristles up to 2.4 cm long; seeds reniform, about 5 mm long and 3.5 mm wide, verrucose.
Datura kymatocarpa is restricted to the Rio Balsa valley, Mexico.
Reference:
Barclay AS (1959) New considerations in an old genus: Datura. Botanical Museum Leaflets, Harvard University 18: 245-272. Stable URL: https://www.jstor.org/stable/41762193.