Poa labillardierei Steud.
rough poa tussock
Coarse, dense, green or blue-green often very scabrid tussocks, to c. 120 cm, with a large bulk of dead dry leaves densely packed at the narrow base; branching intravaginal; leaf-blades persistent. Leaf-sheath light greenish brown, later grey-brown, rarely slightly purplish, subcoriaceous, ± distinctly ribbed, ± minutely scabrid. Ligule 0.2-0.6 mm, truncate, minutely ciliate, abaxially scabrid. Leaf-blade 35-65 cm × 1.8-3 mm, coriaceous, flat, to folded and ± inrolled, abaxially usually scabrid, occasionally almost smooth, adaxially finely ribbed, finely scabrid on ribs; margins obviously scabrid, tip ± acicular, straight-sided. Culm 60-110 cm, erect or drooping, internodes scabrid below panicle. Panicle 10-25 cm, open; branches fine, not drooping, slightly spreading, finely scabrid, in clusters of 3-7, naked and undivided below, with numerous spikelets clustered at tips. Spikelets 3-7 mm, 3-5-flowered, light green, often purplish. Glumes usually ± equal, 1.5-3.5 mm, 3-nerved, often scabrid near tip and on midnerve and margins, narrow- to ovate-lanceolate, acute. Lemma c. 2-4 mm, 5-nerved, oblong-elliptic, obtuse, ± short scabrid but usually softly hairy on midnerve and lateral nerves near base. Palea 2-3.5 mm, keels scabrid in upper ⅔ and smooth below, interkeel scabrid. Callus with long tuft of soft tangled hairs. Rachilla slightly > 0.5 mm, minutely scabrid with some longer hairs; prolongation sometimes twice as long. Lodicules 0.5-0.6 mm. Anthers 1-2 mm. Caryopsis 1-1.5 × 0.5-1 mm.
N.: scattered and local from North Auckland to Bay of Plenty and Mt Egmont, and in the Wairarapa and Wellington; S.: scattered in east near Blenheim, Waipara, and on Banks Peninsula; more common in Central and South Otago and in Southland. Lowland to montane in modified tussock grassland and waste ground.
Naturalised from Australia.
Poa labillardierei was first recorded for N.Z. under the name P. australis agg. which was applied for a long time in Australia to large tussock-forming spp. of Poa.
Poa labillardierei is very variable and at least 3 forms are present in N.Z.: a) large plants with broad green leaves in Hutt Valley, on the Port Hills near Christchurch, in Central Otago and also in Marlborough, where the leaves are barely scabrid; b) very large, very scabrid plants with broad blue-green leaves also on the Port Hills and in Central Otago; c) plants with narrow green leaves in Central Otago.
