Erect or ascending perennial herb 25–40(–70) cm high; branches glabrous to sparsely appressed-pilose. Leaves 9–21-foliolate, narrowly obovate to oblanceolate, mostly 8–15 cm long; leaflets ovate to oblong, the largest 4–23 mm long, 3–13 mm wide, margins deeply lobed or serrate, flat or recurved, upper surface glabrous or sparsely pilose, lower surface sparsely pilose, mostly on veins and margins; stipules linear to triangular, 1–6 mm long. Inflorescence an interrupted cylindric spike, occasionally branched; peduncles glabrescent to sparsely pilose; sepals 4–6, usually 5; stamens 2–8, dark purple; style 1, rarely 2. Fruiting hypanthia ovoid or with longitudinal ridges formed by the concrescence of spine bases, glabrous or pilose; spines unequal, 3–8 mostly near apex 2–5 mm long, 8–30 mostly lower down 0.5–2 mm long. Flowers and fruits Aug.–Apr.
LoM, MuM, Wim, GleP, Brid, VVP, VRiv, GipP, OtP, WaP, Gold, CVU, GGr, DunT, NIS, EGL, EGU, WPro, HSF, HNF, OtR, Strz, MonT, HFE, VAlp. Also WA (?introduced), SA, Qld, NSW, Tas. Except for the far north-west and wetter forest areas, widespread across much of the State.
Orchard (1969) recognized 5 varieties-var. echinata (glabrous fruit, short stamens, small stipules), var. robusta (glabrous fruit, long stamens, large stipules), var. subglabricalyx (pilose fruit with slender spines), var. retrorsumpilosa (pilose fruit with basally thickened spines, short stamens, small stipules) and var. tylacantha (pilose fruit with basally thickened spines, long stamens, large stipules). All 5 of these have been recorded for Victoria and intermediates often occur. In the absence of mature fruits, the 5 varieties are difficult to determine with any degree of confidence.
Apparently Acaena echinata hybridises with A. agnipila to form Acaena ×ovina (Orchard 2018).
