Flora of New Zealand Series

Glabrous dioecious perennial, ± reddish, with a slender branched rhizomatous system; stems erect, to c. 25 cm long. Petioles long and slender on lower lvs, much shorter on upper lvs. Lamina linear, usually 10-40 × 1-2 mm (excluding lobes), entire except for narrow, spreading basal lobes to c. 1.5 cm long; margins inrolled except when young; apex acute. Upper lvs smaller and very narrowly linear. Infl. to c. 12 cm long, with slender branches, leafless except near base. Fls fascicled. Pedicels slender, glabrous. Perianth of ♂ fls 0.8-1.2 mm long. Outer perianth whorl of ♀ fls c. 0.5 mm long, not reflexing at fruiting; inner perianth whorl erect, enlarging at fruiting. Fr. valves c. 1.3 mm long, suborbicular, entire; tubercles 0. Nut c. 1.5 mm long, ± crimson, sharply angled.

S.: Waipara and Waiau (N. Canterbury), around Christchurch, Lowburn (C. Otago).

Europe 1968

Mostly dry stony soil on waste land or in riverbeds, apparently uncommon.

FL Nov-Mar.

R. tenuifolius is a segregate from R. acetosella and possibly only represents a form of the ordinary sheep's sorrel with a more decumbent habit and very narrow, inrolled lvs [ see, den Nijs, J. C. M. and Panhorst-Sangster, T., Acta Bot. Neerl. 29: 179-192 (1980)]. However, the plants appear to be distinct; they sometimes occur together with more typical R. acetosella and no plants of intermediate character are present. Also, in some parts of Europe, lf width is correlated with the fusion or otherwise of the inner perianth segments to the nut [Harris, W., New Zealand J. Bot. 11: 141 (1973)]. Furthermore the 2 spp. have different chromosome numbers (R. acetosella 2 n = 42, R. tenuifolius 2 n = 28).