Flora of New Zealand Series

≡P. imbecilla var. matthewsii (Petrie) Hack. in Cheeseman Man. N.Z. Fl. 913  (1906)

≡P. matthewsii Petrie var. matthewsii (autonym Petrie 1902 op. cit. p. 393); 

Lectotype: WELT 66983! D. P[etrie] Waipahi, S. Otago, by banks of river (designated by Edgar 1986 op. cit. p. 470).

=P. matthewsii var. tenuis Petrie, T.N.Z.I. 34: 393 (1902); 

Lectotype: WELT 66929! D. Petrie Catlin's River, Otago, sea level, Dec. 1891 (designated by Edgar 1986 op. cit. p. 470).

Markedly stoloniferous perennial, with bright green, rarely glaucous leaves, tending to lie along the ground, and very slender culms erect or geniculate and ascending, to 50 cm; branching extravaginal; leaf-blades persistent. Leaf-sheath pale green to light brown, membranous, mainly glabrous but with minute hairs and prickle-teeth near hyaline margin, occasionally near ligules and on keel. Ligule 0.7-1.5 mm, apically glabrous, entire, rounded, abaxially with dense, minute hairs. Leaf-blade (5.5)-10-17 cm × 1-2 mm, flat, soft, abaxially glabrous, adaxially with very minute fine hairs; margins ciliate near ligule, midrib minutely scabrid especially near filiform, acuminate tip. Culm 10-25-(36) cm, internodes very minutely scabrid just below panicle or rarely smooth. Panicle 10-25 cm, lax and delicate; rachis very minutely, sparsely scabrid, branches finely scabrid, spreading, with few spikelets at tip. Spikelets 3.5-5-(6) mm, (2)-3-4-(5)-flowered, green, rarely purplish. Glumes unequal; lower 0.8-1.5 mm, 1-nerved, narrow-lanceolate, subobtuse, upper 1.5-2 mm, 3-nerved, elliptic-lanceolate, obtuse, midnerve scabrid. Lemma 2-3 mm, 5-nerved, narrow-lanceolate, subobtuse, nerves minutely scabrid above, lateral nerves occasionally with long hairs near base, internerves glabrous. Palea 1.5-2 mm, keels ciliate-scabrid, interkeel ± minutely hairy. Callus glabrous, or often with a few fine long hairs. Rachilla 0.5-1 mm, glabrous or with a few hairs. Lodicules 0.2-0.4 mm. Anthers 0.3-0.5 mm. Gynoecium: ovary 0.3-0.5 mm; stigma-styles 1.0-1.25 mm. Caryopsis c. 1 × 0.3 mm. 2 n = 28. Plates 4D, 7B.

N.: South Auckland (Mangapu Caves), and central and southern regions; S.: east of Main Divide and in north-west Nelson. Lowland to montane in open forest, often not far from the coast.

Endemic.

Poa matthewsii is morphologically close to P. imbecilla in its delicate leaves and panicle, almost glabrous spikelets and minute anthers, but can be distinguished by its stoloniferous habit and by the scabrid hyaline margins of the leaf-sheath.