Gaz. Lit. México 3(suppl.): 4. 1794
Subshrubs, to 1 m, dioecious, rhizomatous, often forming colonies. Stems spreading, reddish brown (when actively growing) or red to dark red or grayish (when dormant), much-branched, rubbery-succulent, glabrous; short shoots common; latex watery, colorless to cloudy-whitish in fast growing shoots, blood red in basal portion of older shoots and rhizomes. Leaves deciduous, fascicled on short shoots; stipules deciduous, linear, 1–2 mm, undivided; petiole 0–0.2 cm, not stipitate-glandular; blade linear-spatulate to narrowly obovate, 1.5–5(–7) × 0.2–0.7 cm, usually unlobed, sometimes shallowly, rarely deeply, 3-lobed, base attenuate, margins entire, apex rounded, membranous, surfaces glabrous; venation pinnate (palmate if lobed). Inflorescences terminal or axillary, fascicles; peduncle absent; bracts absent. Pedicels 1–2.5 mm. Staminate flowers: sepals distinct or connate basally, ovate to elliptic-lanceolate, 2.5–3 × 1.2–1.4 mm, margins entire, apex acute, abaxial surface hairy, adaxial glabrous; corolla white to pinkish white, urceolate-tubular, petals connate most of length, 5–6 × 1.4–1.5 mm, abaxial surface sparsely puberulent abaxially, adaxial glabrous; stamens 10 in 2 whorls (5 + 5); filaments of both whorls connate from 1/5–3/4+ length, outer whorl 2–3 mm, inner whorl 3–5 mm. Pistillate flowers resembling staminate; carpel 1; style 2.5–3 mm. Capsules ellipsoidal, 1.2–1.4 × 1.1–1.3 cm, tardily dehiscent. Seeds solid gray-brown, spheric, 12 mm diam.; caruncle rudimentary. 2n = 44.
Tex., n Mexico.
Varieties 2 (2 in the flora).
R. McVaugh (1945b) recognized two varieties in Jatropha dioica based primarily on leaf shape; the two are not readily recognizable and probably hybridization between them has resulted in intermediate populations, as McVaugh noted. The varieties are treated here with some reservation.
|1||Leaf blades oblanceolate to narrowly obovate, 3.5–5(–7) cm; sepals distinct; stamen filaments connate 3/4+ length; petals pinkish white.||Jatropha dioica var. dioica|
|1||Leaf blades linear-spatulate, 1.5–2.5 cm; sepals connate basally; stamen filaments connate to 1/4 length; petals white.||Jatropha dioica var. graminea|