Flora of New Zealand Series

≡Petriella Zotov, T.R.S.N.Z. 73: 235 (1943) non Curzi (1930).

Type species: Z. colensoi (Hook.f.) Edgar et Connor

Rhizomatous perennials, compact, cushion-like, with close-set leaves, sometimes forming tufts from trailing culms; branching intravaginal. Leaf-sheath cross-veinlets few. Auricles fringed with some long fine hairs, or auricles 0. Ligule a minute ciliolate rim, or ciliate. Leaf-blade flat or inrolled, cross-veinlets prominent. Inflorescence a contracted panicle or reduced to a raceme. Spikelets laterally compressed, shortly pedicelled, falling entire from above persistent subequal glumes; 3-flowered, 2 lower reduced to unequal awned Ø lemmas; uppermost floret ⚥, awnless; rachilla minutely prolonged. Glumes = ½ length of florets, ovate, subcoriaceous, smooth; lower usually faintly 3-nerved, upper usually faintly 5-nerved. Ø lemmas narrowly ovate-lanceolate, slightly narrowed above to a short, relatively thick, scabrid awn, cartilaginous, abaxially smooth or scarcely scabrid, adaxially minutely pubescent, keel smooth or scabrid, shortly hairy callus at base; lower Ø lemma 5-7-nerved; upper Ø lemma longer, usually 7-nerved. ⚥ lemma ≥ lower Ø lemma, ≤ upper Ø lemma, slightly broader, ovate-lanceolate, awnless, subcoriaceous, smooth, but sometimes ± scabrid on midnerve, faintly 5-7-nerved, callus smooth. Palea membranous with 2 close-set central nerves. Lodicules 2, finely many-nerved in lower ½. Stamens 2. Styles free naked below; stig-mata plumose. Caryopsis narrow-oblong; embryo c. ⅕ caryopsis; hilum ≈ caryopsis.

3 spp., endemic to New Zealand; usually subalpine to alpine, in damp ground.

The flowers of Z. colensoi are correctly illustrated by Buchanan, J. Indig. Grasses. N.Z. t. 1 (1878) as are those of Z. thomsonii by the same artist in Petrie, D. T.N.Z.I. 12: t. 10 (1880).

The treatment here is that of Edgar, E. and Connor, H. E. N.Z. J. Bot. 36: 568-586 (1998).