Annual or biennial herb up to 1 (1·5) m. tall; stems ± woody, pale green or brownish-purple, shortly stellate-tomentose and sparsely setose when young, branched from the base. Leaves dark green, usually with a purplish margin, minutely pubescent above with stellate or simple hairs, usually minutely stellate-pubescent beneath; lamina of lower leaves 12 × 12 cm., ovate-orbicular in outline, base truncate or slightly cordate, 5-lobed or -angled; lamina of middle leaves ovate in outline, 3–5-palmatisect to -palmatipartite, lobes rhombic, obovate or oblanceolate; lamina of upper leaves 3–6 cm. long, scarcely lobed, lanceolate, margin serrate, base cuneate; petiole up to 12 cm. long, hairy like the stems; stipules c. 10 mm. long, subulate-setose. Flowers 3–6 cm. in diam., yellow with dark red centre, solitary, axillary or forming racemes at the apices of the stems; peduncle up to c. 5 mm. long, hairy like the stems, articulated near the base. Epicalyx of 8–12 bracts; bracts c. 10 mm. long, linear, apices sometimes shortly appendiculate but not manifestly forked, joined at the base. Calyx c. 15 mm, long; lobes ovate-lanceolate or triangular, acute, margin tomentellous, midrib with a median gland less conspicuous than that of H. cannabinus, accrescent in fruit and becoming c. 20 mm. long and somewhat woody. Petals 2–4 cm. long, obovate. Staminal tube c. 6 mm. long; free parts of filaments 0·5 mm. long. Style-branches c. 1 mm. long, stigmas hidden among the anthers. Capsule 14–15 × 11–12 mm., ovoid-conical, rostrate, appressed-setose; valves woody. Seeds 3–4 × 3 mm., angular-subreniform. with minute pectinate scales.
