Flora of New Zealand Series

Tufted perennials, with rather stiff, loosely sheathing, erect leaves. Leaf-sheath subcoriaceous, striate, keeled, brown to purplish brown, mainly glabrous, but lowermost sheaths with fine silky hairs, especially near base; sheath apex extended upwards at each margin and fused with ligule. Ligule 1-2 mm, truncate, entire. Leaf-blade 10-20-(30) cm × 3.5-5 mm, often narrower than summit of sheath, flat, rather rigid, midrib obvious, abaxially glabrous, adaxially thickly short-pilose near ligule, with a few very long hairs near margin below; margins finely scabrid, tapered to fine but firm tip. Culm (20)-35-70 cm, usually erect, sometimes semi-prostrate, slightly compressed, internodes glabrous, striate. Panicle erect, 6-12 cm, of 3-8 erect to somewhat spreading ± distant racemes; rachis slender, compressed to angular, finely scabrid on angles above. Racemes (2)-3-4 cm; rachis narrowly winged, with very scabrid margins, 1.2-1.7 mm wide, with short white hairs at base, bearing 2 rows of single or paired, shortly pedicelled or almost sessile spikelets; pedicels sparsely scabrid; paired spikelets usually near centre of raceme. Spikelets 2-2.5 mm, imbricate, ovoid-elliptic to ovoid-orbicular, glabrous, obtuse, light brown. Lower glume 0, upper = spikelet, closely appressed to fertile floret, 3-(5)-nerved, glabrous. Lower floret: lemma = spikelet, 3-(5)-nerved, glabrous; palea 0. Upper floret: lemma c. 2 mm, elliptic-orbicular, cartilaginous-indurate, shining, brown, finely punctulate-striolate; palea ≤ and narrower than lemma, membranous margins widened at base, forming wings enclosing flower; anthers c. 1 mm, yellow to brownish; stigmas dark purple; caryopsis slightly > 1 mm.

N.: North and South Auckland and offshore islands; K.: Raoul Id. In North Id on clay soil, open Leptospermum scrubland, dry banks and waste ground; also on damp ground, particularly seepages. On Raoul Id on thermally heated ground near active fumaroles in Denham Bay, partly shaded tracks, dry forest clearings and open ridges.

Naturalised from Pacific.

Paspalum orbiculare was equated with P. scrobiculatum L., scrobic, an annual Indian sp., by Cheeseman (1925 op. cit.) and treated as indigenous to N.Z. Paspalum orbiculare is widespread throughout the Pacific; Cameron, E. K. Auck. Bot. Soc. J. 53: 40-42 (1998) postulated that it was naturalised in N.Z. because it was initially collected at coastal sites frequently visited by ships and absent from sites rarely visited by humans. Paspalum orbiculare is also recorded from Australia but Vickery, J. W. Contrib. N.S.W. Natl Herb. Flora Series 19(1): 118-119 (1961) regarded Australian plants as differing somewhat in spikelet size and shape from Pacific Is material. N.Z. specimens, however, match Pacific plants in spikelet characters.