6. Jatropha curcas Linnaeus, Sp. Pl. 2: 1006. 1753.
Physic or purging nut, piñón Physic or purging nut, piñón
Trees, to 10[–15] m, monoecious. Stems erect, gray-green, much-branched, woody-succulent, glabrous; short shoots absent; latex watery, colorless in younger branches, cloudy-whitish in older shoots. Leaves persistent, ± evenly distributed on long shoots; stipules caducous, narrowly lanceolate, 5 mm, undivided; petiole 9–19 cm, not stipitate-glandular; blade round in outline, 9–15 × 9–15 cm, usually shallowly 3–5-lobed, rarely unlobed, base cordate, margins entire or glandular (young leaves), apex acuminate, membranous, surfaces glabrous; venation palmate. Inflorescences bisexual, terminal and subterminal, cymes; peduncle 5–10 cm; bracts 3–10 mm, margins entire, glabrous. Pedicels 1–3 mm. Staminate flowers: sepals distinct, ovate-elliptic, 4–6 × 2–3 mm, margins entire, apex acute, surfaces glabrous; corolla greenish yellow, campanulate, petals distinct or connate 1/4 length, 6–8 × 2–3.5 mm, glabrous abaxially, tomentose adaxially; stamens 10, ± in 2 whorls (5 + 5); filaments of both whorl connate to top or nearly so, outer whorl 3–4.5 mm, inner whorl 3–5 mm. Pistillate flowers resembling staminate, but sepals connate to 1/2 length, 5–7.5 × 2–5 mm; petals 4–5 × 2–2.5(–3) mm; staminodes infrequent; carpels 3; styles connate most of length, 0.5–1.5 mm. Capsules ellipsoidal, 2.6–3 × 2.2–2.8 cm, drupaceous. Seeds black or black mottled with white spots, ellipsoidal, 18–20 × 11–13 mm; caruncle rudimentary. 2n = 22 (Puerto Rico).
Flowering and fruiting spring (late summer–early fall). Disturbed sites; 0–50 m; introduced; Fla.; Mexico; Central America; introduced also in West Indies, South America, Asia, Africa, Pacific Islands, Australia.
Jatropha curcas now has a circumtropical distribution but probably originated in Central America; it is naturalized in southern Florida. The latex of J. curcas is used for soap making and for medicinal purposes; the seeds are used for biofuel production.