Slender suffruticose perennial with dark brown subterranean stems < 2 mm diam. Branches prostrate and < 50 cm long, or erect and < 5 cm long, c. 0.7 mm diam., brown, hirsute, epidermis flaking with age; internodes < 3.5 cm long on prostrate stems. Leaves hairy; stipules 2-6 mm long, margins, tips and abaxial face hairy, free portion linear, entire or bifid, < sheath; leaflets 3 or 4 pairs, the distal leaflet and 2 upper pairs obovate to suborbicular in outline, truncate at apex, shallowly cuneate at base, 2-10 × 2-6 mm; upper surface dull green, glabrous, smooth, with secondary venation indistinct; lower surface pale, glaucescent, the veins with appressed hairs; teeth 7-9 with margins thickened and recurved, hydathodes pink. Basal leaflet pairs less than lh the size of the penultimate pair, or linear and smaller than stipule lobes. Hairs simple, unicellular, < 1.5 mm long, on stipules, rachis and leaflets. Scapes terminal on short shoots, 4-13 cm long at flowering, hardly elongating as fruit matures, c. 0.5 mm diam., moderately hairy, pale brown. Scape bract linear or foliose, occasionally subtending a single floret. Capitulum 4-6 mm diam. at flowering, 10-15 mm diam. (including spines) at fruiting. Bracteoles on receptacle linear, c. 3 mm long, with hairy margins. Florets c. 40-50, minutely stipitate. Hypanthium c. 1 mm long, enclosing perigynous ovary, densely hairy, bearing 4 barbed spines which reach above the hypanthium rim. Sepals 4, arising from hypanthium rim, shortly joined at base, c. 1.5 mm long, elliptic, narrowed and thickened at tip, sparsely hairy on abaxial face. Petals 0. Stamens 2; filaments unequal, up to 2 mm long; anthers 0.3 × 0.5 mm, white. Style 1, 1.5 mm long, including white, fimbriate stigma 0.6 mm broad and protruding from aperture of hypanthium. Fruit indehiscent with a single achene enclosed in the hypanthium, obconic, c. 2 × 1.2 mm, brown, moderately hairy, 4-ribbed; spines 1 per rib, slender, 4-6 mm long, pale rose or brown, bearing a single rank of translucent, retrorse barbs at tip.

Suffrutex tenuis; caules c. 0.7 mm diam., ad 50 cm longi; proni et radicantes. Folia ad 5 cm longa, imparipinnata; foliola 7-9, foliola distalia quinque obovata vel suborbiculata, supra viridia, laevia, subtus pallida, sericea, dentibus crenatis et politis; stipuli integri vel befidi. Scapus c. 10 cm longus. Stylus albus. Antherae albae. Fructus c. 2 × 1.5 mm, pilosus. Inter species sectionis Ancistrum bene evolutis glochideis fructus spinis carpelloque singulari. Differt a A. anserinifolia foliorum forma, crenis, stipulis integris, fructibus minoribus.

Slender suffruticose perennial with red brown or dark brown subterranean stems < 1.5 mm diam. Branches prostrate and < 30 cm long, or erect and < 10 cm long, c. 1 mm diam., light red brown, clad in simple, ascending to erecthairs, epidermis broken with age; internodes < 3 cm long on prostrate stems. Leaves imbricateon short erectshoots, imparipinnate, (1.5)-3.5-5 × (0.7)-1.7 cm; stipules 4-7 mm long, margins, tips, and abaxial face hairy, free portion acuminate, entire or bifid, ± = broad sheath; leaflets (1)-3-5 pairs, the distal leaflet and one or two upper pairs suborbicular in outline, truncate at apex, shallowly cuneate at base, 4-15 × 3-11 mm; upper surface dull, rich green, punctate with raised hair bases, and with distinct veins, lower surface glaucescent, moderately clad in ascending hairs; teeth 8-14, sharply incised, often red brown at least on margins, shortly penicillate, with white or pink hydathodes. Basal leaflet pairs < ½ the size of the penultimate pair, or linear and entire, smaller than stipule lobes. Hairs simple, unicellular, < 1.5 mm long, ascending from raised bases, on stipules, rachis, and leaflets. Scapes terminal on short shoots, (4)-7-15 cm long at flowering, hardly elongating as fruit matures, moderately hairy and roughened by raised hair bases, pale brown. (Frequently a second scape is produced from the axil of an upper leaf in the same season so that the shootappears forked). Scape bract 0, or foliose, occasionally subtending a single floret. Capitulum 6-8 mm diam. at flowering, 10-15 mm diam. (including spines) at fruiting. Bracteoles on receptacle linear, c. 3 mm long, with hairy margins. Florets c. 45-60, minutely stipitate. Hypanthium c. 1 mm long, enclosing perigynous ovary, clad in appressed hairs and bearing 4 barbed spines which reach above the hypanthium rim. Sepals 4, arising from hypanthium rim, joined at base to form a short tube, 1.2 mm long, ovate, thickened at tip, hairy on abaxial face. Petals 0. S tamens 2; filaments unequal, up to 2.5 mm long; anthers c. 0.4 × 0.5 mm, white. Style 1, 1.5 mm long, including white, fimbriate stigma 0.7 mm broad and protruding from aperture of hypanthium. Fruit indehiscent with a single achene enclosed in the hypanthium, obconic, c. 2.5 × 1.5 mm, red brown, moderately hairy, 4-ribbed; spines 1 per rib, slender, 4-6 mm long, pale brown, bearing a single rank of translucent, retrorse barbs at tip.

Suffrutex tenuis; caules c. 1 mm diam., ad 30 cm longi, proni et radicantes. Folia ad 5 cm longa, imparipinnata; foliola (3)—7—11, foliola distalia tria suborbiculata, supra viridia, punctata, subtus glaucescentia, pilis ascendentibus; dentibus penicillatis; stipuli integri vel bifidi. Scapus c. 7 cm longus. Stylus albus. Antherae albae. Fructus c. 2.5 × 1 mm, pilosus. Inter species sectionis Ancistrum bene evolutis glochideis fructus spinis carpelloque singulari. Differt a Acaena anserinifolia foliorum forma, stipulis integris, pilis ascendentibus, fructibus minoribus.