Compilation
Acanthus montanus

Perennial herb to 1(–2) m tall with creeping rhizome; young stems somewhat fleshy, subglabrous to sparsely sericeous or sparsely puberulous. Leaves with petiole 0.5–2.2(–2.8) cm long; lamina elliptic to obovate in outline, largest 14–30≈5–15 cm, varying (sometimes on the same stem) from unlobed with remotely denticulate margin to deeply lobed with oblong to triangular spine-tipped lobes, each lobe with 1–3 teeth on antrorse or on both sides, apex acuminate to cuspidate, spine-tipped, base attenuate to truncate with pair of large spines right at base and sometimes detached, sparsely puberulous (rarely pubescent) on midrib and larger veins, on lamina with scattered stiff erect bulbous-based hairs making surface rough to the touch, above sometimes without stiff hairs; alternate pair(s) of leaves absent. Cymes solitary, 3–15(–26) cm long (rarely with only 2–4 flowers apically on stem); rachis glabrous to puberulous, without or with 1-several pairs of sterile bracts at base; bracts green or purple-tipped or -mottled, elliptic-obovate, sparsely and minutely to densely puberulous, 2.5–4.7 cm long in middle of cyme of which the long triangular straight or recurved spine-tipped apical part 0.9–2.2(–3) cm, with 4–12 large and small teeth per side (sometimes small absent), longest 3–8 mm, small teeth inserted between large; bracteoles linear to linear-lanceolate, 1.4–2.8 cm long, entire or with 1–3 teeth per side. Calyx green or with purple apical part and sometimes veins, glabrous to puberulous; dorsal sepal ovate to elliptic, narrowing gradually or with parallel-sided apical part, 3.4–4.6 cm long, acute (rarely 2-toothed), no lateral teeth, ventral oblong-elliptic, narrowing gradually or with parallel-sided apical part, 2.6–3.8 cm long, bifid with 2 triangular teeth 1–4 mm long (these sometimes with 1–2 small additional teeth), without (very rarely with a single) lateral teeth, lateral lanceolate to narrowly ovate, 1.1–2.3 cm long, cuspidate, without (rarely with a single) lateral teeth per side. Corolla pale pink to pink or mauve (rarely white with pink veins); tube 3–6 mm long below thickened rim which is 3–6 mm long and with a broad shallow split dorsally without tooth; limb spreading, 5-lobed, 3–4.5≈2.5–5 cm, below glabrous to sparsely puberulous, towards base with large glandular swellings, above glabrous; callus not grooved. Filaments 1.5–2.5 cm long, glabrous; anthers 7–10 mm long, without or with sparse long curly hairs on sides and without or with sessile glands dorsally. Capsule ± 2.5 cm long. Seed rhomboid, 7–8 mm long, sericeous.