Flora of New Zealand Series

tall oat grass

Loosely tufted, coarse perennials, (40)-60-150 cm. Leaf-sheath ± chartaceous, smooth, or rarely minutely scabrid, sometimes with scattered long fine hairs. Ligule 1-3-(4) mm, truncate to ± obtuse, erose, ± ciliate, abaxially minutely scabrid to minutely hairy. Leaf-blade 15-30-(50) cm × 2-12 mm, minutely scabrid on ribs, to ± smooth, adaxially often with scattered long fine hairs; margins minutely, closely scabrid, tip acute, scabrid. Culm erect or ± spreading, stout. Panicle (4)-14-32 cm, erect or nodding, dense or lax, slender and lanceolate or with lower branches spreading; rachis smooth below, scabrid above, branches and pedicels slender, scabrid. Spikelets 7.5-9.5-(11) mm, shining, green or purplish. Glumes acute, sometimes finely scabrid, nerves finely scabrid; lower (3.5)-4.5-6-(6.8) mm, lanceolate, 1-nerved, upper ≤ spikelet, ovate-lanceolate, 3-nerved. Lemma (7)-8-9 mm, 7-nerved, ovate-lanceolate, hyaline near acute tip, nerves distinct, finely scabrid, upper or both lemmas with scattered fine hairs in lower ½; awn of lower lemma 8-16.5 mm; awn of upper lemma 0.5-10 mm, or 0. Palea narrower than lemma, keels finely ciliate, interkeel minutely scabrid, apex shortly bifid. Callus usually ringed by short stiff hairs. Rachilla prolongation 1.5-2.5 mm, delicate, glabrous. Anthers 3.5-5 mm. Gynoecium: ovary 0.6-0.8 mm; stigma-styles 1.5-1.8 mm. Caryopsis 2.5-3.8 × 0.8-1.2 mm.