Classification
Class
Magnoliopsida Brongn.
Order
Poales Small
Family
Gramineae Juss.
Genus
Microlaena R.Br.
 Nomenclature
Scientific Name:
Microlaena avenacea (Raoul) Hook.f., Handb. New Zealand Fl. 320 (1864)
Synonymy:
  • ≡ Diplax avenacea Raoul, Ann. Sci. Nat., Bot. sér. 3, 2: 116 (1844)
  • ≡ Ehrharta diplax F.Muell. (1870)
Vernacular Name(s):
Bush rice grass; Oat grass
 Description

Caespitose wide-leaved perennial from short rhizome with long culms and large inflorescences. Branching extravaginal, occasionally with stolons rooting at nodes; cataphylls broad and shining. Leaf-sheath smooth or sometimes scabrid; keel stout, often prickled towards apex. Ligule to 0.5 mm, membranous, crenate or shallowly toothed, broadly triangular, ciliolate. Auricle 1, ± 5 mm, margin hairs 2–4 mm. Leaf-blade to 50 cm × 6–12 mm wide, bright green, keel strong, sometimes scabrid below; sharp, fine, close-set, dense antrorse prickles on margins above becoming smooth below except for auricle hairs extending for c. 1 cm; abaxially rough occasionally scabrid, occasional prickle-teeth near ligule. Culm to 1.25 m; internodes laterally compressed and conspicuously, longitudinally grooved, smooth to finely prickle-toothed. Panicle 25–65 cm, nodes widely spaced, branches filiform, > internodes; nodes with short branches of close-set spikelets and long flexuous branches to 20 cm, naked below; rachis longitudinally grooved, finely scabrid to ± smooth, branches and pedicels finely prickle-toothed. Spikelets 18–30 mm, solitary, on short or long pedicels. Glumes unequal, 1-nerved occasionally 3-nerved, margins ciliate, entire or 2 or 3-toothed especially upper; lower to 1 mm, = callus hairs, upper 1–2.5 mm > callus hairs. Lower Ø lemma 9–15–25 mm, 5-nerved, prickle-toothed especially on keel, adaxially hairy above, awn > ½ lemma length; callus hairs to 1 mm; upper Ø lemma 12–23–27 mm, 3-nerved, scabrid above, awn > ½ lemma length; callus hairs 1–2 mm. ☿ lemma 5–7–12 mm, 3-nerved, awnless and ciliate or occasionally shortly (0.5–2 mm) awned from bifid apex; callus hairs few and short. Palea 3–4–5 mm, membranous, acute, upper margins and apex ciliate. Lodicules 2, 0.6–1.2 mm, > ovary, lobed occasionally flabellate, truncate and finely erose, occasionally lobes long hairy, persistent or falling with caryopsis. Stamens (1)–2, anthers (1)–2–3–(4) mm. Gynoecium: ovary 1 mm; stigma-styles 1–1.5–2.5 mm, styles naked below. Caryopsis 2–3.5–5 mm, often falling free; embryo 0.5–0.7 mm. 2n= 48. Fig. 2. Plate 6C.

[From: Edgar and Connor (2000) Flora of New Zealand. Volume 5 (second printing).]

 Biostatus
Indigenous (Non-endemic)
 Bibliography
de Lange, P.J.; Rolfe, J.R.; Barkla J.W.; Courtney, S.P.; Champion, P.D.; Perrie, L.R.; Beadel, S.N.; Ford, K.A.; Breitwieser, I.; Schönberger, I.; Hindmarsh-Walls, R.; Heenan, P.B.; Ladley, K. 2018: Conservation status of New Zealand indigenous vascular plants, 2017. New Zealand Threat Classification Series. No. 22. [Not Threatened]
de Lange, P.J.; Rolfe, J.R.; Champion, P.D.; Courtney, S.P.; Heenan, P.B.; Barkla, J.W.; Cameron, E.K.; Norton, D.A.; Hitchmough, R.A. 2013: Conservation status of New Zealand indigenous vascular plants, 2012. New Zealand Threat Classification Series 3. Department of Conservation, Wellington. [Not Threatened]
Hooker, J.D. 1864: Handbook of the New Zealand Flora: a systematic description of the native plants of New Zealand and the Chatham, Kermadec's, Lord Auckland's, Campbell's and Macquarie's Islands. Part I. Reeve, London.
Raoul, E. 1844: Choix de plantes de la Nouvelle-Zélande. Recueillies et décrites par M.E. Raoul. Annales des Sciences Naturelles; Botanique sér. 3, 2: 113–123.