Flora of New Zealand Series

≡P. anceps var. chathamica (Petrie) Zotov, T.R.S.N.Z. 73: 236 (1943); 

Holotype: WELT 66386a! L. Cockayne 6575 & F. A. D. Cox growing on sphagnum or very boggy ground, S. end of Chatham Island (No 1473 to Hackel).

Dense, drooping perennial swards from long, narrow rhizomes, or stiff tufts to 90 cm, with light green leaves ≈ culms; branching extravaginal near plant base, intravaginal above; leaf-blades persistent. Leaf-sheath light green to light brown or straw-coloured, coriaceous, ribbed, smooth to finely scabrid, keeled. Ligule (0.2)-0.5-1 mm, a truncate stiff ciliate rim, abaxially with matted stiff minute hairs. Leaf-blade 5-30 cm × 2.5-4.5 mm, folded to flat, or inrolled and c. 1 mm diam., coriaceous, abaxially smooth, adaxially ribbed, covered with short prickle-teeth and sometimes short stiff hairs; margins ± thickened, smooth to sparsely scabrid, midrib scabrid near straight-sided, pungent tip. Culm 10-80 cm, internodes smooth, densely scabrid below panicle. Panicle 5.5-12 cm, lax or contracted; branches spreading or erect, sparsely to densely scabrid. Spikelets 6.5-14.5 mm, (2)-3-5-flowered, greyish green to light greenish brown. Glumes subequal, 3-nerved, elliptic-lanceolate, acute to acuminate, often with minute fine hairs near tip, occasionally scabrid throughout, midnerve ciliate-scabrid especially on upper ½; lower 4.5-7.5 mm, upper 4.5-8 mm; margins ciliate. Lemma 4.5-9 mm, 5-nerved, elliptic- to oblong-lanceolate, subobtuse to subacute, scabrid above or occasionally throughout, midnerve with long fine hairs to ½ length, lateral nerves hairy near base; margins minutely ciliate. Palea 3.5-7.5 mm, keels rather stiffly ciliate-scabrid, interkeel with sparse minute hairs. Callus with loose web of long fine crinkled hairs. Rachilla 0.5-1 mm, glabrous to sparsely minutely pubescent; prolongation twice as long. Lodicules 0.5-2 mm, occasionally hair-tipped. Anthers 2-3.5 mm. Caryopsis 2 × 0.5 mm. 2 n = 112.

Ch. Rocky sites on coast and inland, sand dunes, and open sites in peat.

Endemic.

Although plants of P. chathamica vary considerably in habit, it is impossible to subdivide the species. Plants growing on the sandy foreshore at Kaingaroa (e.g., CHR 95402, CHR 96577) are distinct in having the following features in combination: a very contracted panicle with densely scabrid branches and glumes, long spikelets, and short ligules. However, there is no clear-cut separation between plants from sandy ground and others from cliffs or peat.