Shrub to 3(–4) m tall; young stems puberulous or sparsely so. Leaves with petiole 0.5–1(–2) cm long; lamina elliptic or narrowly so in outline, largest 10–19≈5.5–9 cm, deeply lobed with large triangular spine-tipped lobes, each lobe with a single spine on antrorse side, apex acute, spine-tipped, base truncate, beneath puberulous or sparsely so and with longer glossy hairs on midrib and larger veins, glabrous on lamina, above puberulous on midrib, otherwise glabrous; stipule-like interpetiolar leaves present (rarely absent), with lamina up to 7 mm long, spiny, soon caducous. Cymes 7–17(–20 in fruit) cm long; rachis sericeous-tomentose, with several pairs of sterile bracts at base; bracts with 3 prominent longitudinal veins, brown to purple, obovate, sparsely sericeous-puberulous or -pubescent, 2.7–3.7 cm long in middle of cyme, spine-tipped and with 15–28 large and small teeth per side, longest 8–12 mm, small teeth inserted on large, teeth with scattered hairs near base only, less than 1 mm long; bracteoles lanceolate to obovate, 3.2–3.8 cm long, toothed in apical 1/2–3/4 with up to 25 teeth per side. Calyx green with purple apical part and teeth and yellow thickened part, sparsely to densely sericeous-pubescent; dorsal sepal 1–3-veined, ovate with long parallel-sided apical part, 3.5–4 cm long, acute, with 3–20 lateral teeth per side, longest tooth 3–5 mm long, ventral sepal 2-veined, obovate, 3.4–3.8 cm long, with 2 triangular lobes which are acute or 2–4-toothed and ± 8 mm long, with 6–17 lateral teeth per side, longest tooth ± 6 mm long, lateral sepals 1-veined, ovate-elliptic, 2.2–2.7 cm long, acuminate, without or with up to 12 lateral teeth per side (one side often with more than the other). Corolla tube white, limb deep purple; tube 6–7 mm long below thickened rim which is 8–10 mm long and deeply split dorsally; limb deflexed, 4–5.5≈3–3.5 cm, finely and sparsely puberulous above and below; callus with broad central groove and two narrow lateral ridges. Filaments 2.7–3.3 cm long, glabrous; anthers, 4–5.5 mm long, with sparse long curly hairs on sides and sessile glands dorsally. Capsule ± 3 cm long. Seed (immature) discoid, glabrous, ± 8≈6 mm.
