Acaena inermis Hook.f.
A. microphylla var. inermis (Hook. f.) Kirk Stud. Fl. 1899, 134.
Type locality: Nelson. Type: K, Bidwill. The type specimen is very imperfect, now lacking achenes.
Main stems stout, creeping and rooting, up to 1 m. or more long, branches ascending, short, seldom > 5 cm. long, sparsely hairy to glab. Lvs up to 5 cm. long, 7-15-foliolate, glab. to slightly hairy, stipules unidentate. Lflts crenate-dentate, above purplish to olive- or bronze-green (bright green in shade), below glaucescent; upper pair up to 5 mm. long, subsessile, suborbicular to broad-ovate, petiolule of terminal lflt up to 3 mm. long. Scapes pubescent to glab., up to 7 cm. long; bracts minute or absent. Heads up to 1 cm. diam., bracts linear, ± pilose. Cupules pilose to glab., c. 1-2 × 1-2 mm., turbinate, angles thickened. Spines absent. Sepals olive- to brownish-green, ovate, obtuse to subacute. Stamens 2, anthers white. Styles fimbriate on one side.
DIST.: S. Montane riverbed and tussock-grassland throughout, mainly east of divide.
Bitter (loc. cit. 1911, 287) distinguishes forms breviscapa, with scapes up to 7·5 mm. long; longiscapa, with scapes 3 cm. or more long. The long-scaped form is by far the most common; the status of the short-scaped form is uncertain.
Other forms occur that need further study, e.g. a form growing on riverbeds at head of Lake Wakatipu: rather smaller in all parts; lvs pale green above, slightly glaucous below, c. 2 cm. long; scapes nude, glab., c. 3 cm. long; cupule pilose, sepals pale green.
