Cnidoscolus stimulosus

(Michaux) Engelmann & A. Gray

Boston J. Nat. Hist. 5: 234. 1845.

Common names: Tread softly finger rot
Basionym: Jatropha stimulosa Michaux Fl. Bor.-Amer. 2: 216. 1803
Synonyms: Bivonea stimulosa (Michaux) Rafinesque Cnidoscolus urens var. stimulosus (Michaux) Govaerts
Treatment appears in FNA Volume 12. Treatment on page 197. Mentioned on page 198.

Plants 10–120 cm. Leaves: stipules 2–3.5 mm, margins entire; petiole 3–8 cm; blade ovate to round in outline, 5–17 × 4–12 cm, deeply lobed, lobes (1/2–)3/4–9/10 blade length, base broadly cordate to truncate, margins usually dentate, rarely entire, teeth and lobe apices acute to obtuse, not aristate. Staminate flowers: calyx salverform, tube 8–11 mm, distally straight or constricted, stinging hairs absent, lobes 7–10 mm; stamens of outer whorl shorter than inner, filaments of outer whorl distinct, of inner whorl connate most of length; staminodes 0. Pistillate flowers: sepals 10–15 mm; stigmas 12–24. Capsules 10–12 mm. Seeds brown, sometimes mottled, 8–9 mm. 2n = 36.

Phenology: Flowering Mar–Aug.
Habitat: Sandhills, dry sandy woods, sandy old fields.
Elevation: 0–600 m.


V12 1014-distribution-map.jpg

Ala., Fla., Ga., Ky., La., Miss., N.C., S.C., Va.


In Kentucky, Cnidoscolus stimulosus is occasionally naturalized along railroads. Although closely related to C. urens (Linnaeus) Arthur of Mexico, Central America, and South America, C. stimulosus differs in habit, leaf pubescence, and seed shape, and the two are treated here as distinct species.

Selected References


Lower Taxa

... more about "Cnidoscolus stimulosus"
Geoffrey A. Levin +
(Michaux) Engelmann & A. Gray +
Jatropha stimulosa +
Tread softly +  and finger rot +
Ala. +, Fla. +, Ga. +, Ky. +, La. +, Miss. +, N.C. +, S.C. +  and Va. +
0–600 m. +
Sandhills, dry sandy woods, sandy old fields. +
Flowering Mar–Aug. +
Boston J. Nat. Hist. +
Weedy +, Illustrated +  and Endemic +
Bivonea stimulosa +  and Cnidoscolus urens var. stimulosus +
Cnidoscolus stimulosus +
Cnidoscolus +
species +