Flora of New Zealand Series

avalanche grass

; Lectotype: WELT 66379a! L. Cockayne Rolleston R., Westland [7.4.1911] (designated by Edgar 1986 op. cit. p. 448).

Large green perennial clumps or extensive swards, to c. 40-(80) cm, not tussock-forming, stoloniferous between tufts, and shoots ± decumbent at base; branching intravaginal; leaf-blades persistent. Leaf-sheath straw-brown to reddish brown or grey-brown, glabrous, membranous, distinctly ribbed. Ligule c. 0.5 mm, truncate, ciliate, abaxially minutely hairy. Leaf-blade (6)-10-35 cm, flat, to 4.5 mm wide, coriaceous, abaxially glabrous, ribs prominent, adaxially minutely pubescent; margins scabrid or smooth, midnerve scabrid near acicular tip. Culm 20-40-(60) cm, usually < leaves, internodes smooth to slightly scabrid below panicle. Panicle 10-20 cm, very lax with few rather large spikelets in clusters of 2-3 at tips of very slender, widely spreading, pubescent-scabrid branches. Spikelets 7-9.5 mm, 3-5-(6)-flowered, light green. Glumes ± equal, (4)-5-6.5-(7) mm, subacuminate, sparsely short scabrid to smooth, midnerve scabrid in upper ½; lower (1)-3-nerved, narrow-lanceolate, upper 3-(5)-nerved, elliptic-lanceolate; margins membranous with scattered fine prickle-teeth above or almost throughout. Lemma 5-6.5 mm, prominently 5-nerved, elliptic-oblong, obtuse, short-scabrid to pubescent-scabrid throughout, midnerve with long fine crinkled hairs in lower ½, lateral nerves with hairs on lower ⅓; margins membranous sparsely scabrid above or almost throughout. Palea 4-4.5 mm, keels ciliate-dentate, interkeel with minute hairs and prickle-teeth in lower ⅔, flanks smooth to slightly scabrid; margin prickle-toothed near tip. Callus with long tuft of crinkled hairs. Rachilla 1-1.5 mm, almost glabrous with a few prickle-teeth or scattered hairs; prolongation twice as long. Lodicules c. 0.5 mm. Anthers c. 2 mm. Caryopsis c. 2 × 1 mm. 2 n = 112.

S.: along Main Divide, occasionally to east in Marlborough and Canterbury, more common to the west in Westland and also in Fiordland. Alpine to subalpine in grassland, shrubland and damp disturbed stony ground affected by spring avalanches; rarely on coastal cliffs in the south.

Endemic.

Poa cockayneana is very similar to P. cita but is sward-forming not tussock-forming, it has wider flat leaves, larger fewer spikelets, and longer glumes and lemmas. Both spp. frequently grow together but P. cockayneana extends to higher altitudes than P. cita.