Flora of New Zealand Series

Spikelets solitary, or with 1–2 lateral spikelets, 1-fld, peduncle lengthening at maturity, subtended by a lf-like bract. Fl. hermaphrodite, in the uppermost glume. Glumes 3–4, much > fls, deciduous. Hypog. scales 6, in 2 series, ± equal, ± scarious with minutely serrulate margins, remaining attached to the apex of the culm after the nut has fallen. Stamens 3. Style 3-fid, not thickened at the base, deciduous. Nut obovoid, obtuse, smooth with a star-shaped depression round the apiculate tip, or narrowed to a beak at the tip. Perennial herbs, forming dense or loose cushions. Stems densely lfy, much-branched. Lvs , rigid; lamina (at least in N.Z. spp.) broadening and bending forwards from a point a short distance above the top of the sheath; margins for the most part minutely serrulate, but teeth almost lacking from margins at middle part of lf, and ± retrorse towards base near sheath.

A genus of c. 12 spp., mainly of the S. Hemisphere but extending across the equator to Malaya and Hawaii and to Colombia, Panama and Costa Rica. All 3 N.Z. spp. are endemic. Type sp.: O. pumilio R.Br. of Australia. Fl. 11–12. FR. 1–2.

Kükenthal monographed the genus in Fedde Repert. nov. Spec. Regn. veg. 48, 1940, 60–72.