Poa imbecilla Spreng.
≡P. sprengelii Kunth, Révis. Gram. 1: 116 (1829) nom. superfl.
≡Eragrostis imbecilla (Spreng.) Benth., Fl. Austral. 7: 643 (1878) non (R.Br.) Steud. (1854)
≡Poa imbecilla Spreng. var. imbecilla (autonym Cheeseman 1925 op. cit. p. 201);
Holotype: B (Herb. Willdenow no. 1896)! Forster Nova Zelandia.
=P. matthewsii var. minor Petrie, T.N.Z.I. 34: 393 (1902);
Lectotype: WELT 67003a! D. Petrie Manuherikia plain, Vincent Co. & Blacks, same station, Nov. 1899 (No 1463 to Hackel) (designated by Edgar 1986 op. cit. p. 471).
Very fine-leaved, light green, shortly rhizomatous, small, lax, perennial tufts 10-50 cm, with conspicuous light-coloured leaf-sheaths, and slender, erect culms » drooping leaves, topped by extremely delicate, green panicles; branching extravaginal; leaf-blades persistent. Leaf-sheath light green, later creamy brown sometimes purplish, membranous, ribbed, glabrous. Ligule 0.2-0.4-(1) mm, apically glabrous, entire, ± rounded, abaxially slightly scabrid. Leaf-blade (2)-5-12-(16) cm × 0.5-1 mm, folded, usually filiform, soft, culm-leaves 1-3 mm wide, flat, minutely scabrid abaxially on midrib towards long, fine, acute, triangular tip, and adaxially just above ligule and on margins. Culm (4)-10-32-(50) cm, nodes swollen, internodes smooth, rarely scabrid below panicle. Panicle (3.5)-8-15-(25) cm, lax and delicate; rachis smooth to finely scabrid above, elongate branches and pedicels filiform, finely scabrid, spreading, with few spikelets. Spikelets 3-4 mm, 3-4-(5)-flowered, light green, often purplish. Glumes ± unequal, obtuse, midnerve often with a few prickle-teeth; lower 0.8-1.5 mm, 1-nerved, linear-lanceolate, upper 1.3-1.8 mm, 3-nerved, ovate-lanceolate; margins finely scabrid. Lemma (1.6)-1.8-2.2 mm, 5-nerved but inner lateral nerves often rather faint, glabrous, margin and nerves near obtuse tip minutely scabrid. Palea 1.2-2 mm, keels obviously ciliate, interkeel and often margins sparsely prickle-toothed. Callus glabrous, very rarely with a few fine hairs. Rachilla 0.5-1 mm, glabrous. Lodicules c. 0.2 mm. Anthers 0.2-0.4 mm. Gynoecium: ovary 0.3 mm; stigma-styles 0.5-0.9 mm. Caryopsis c. 1 × 0.3 mm, tightly enclosed by lemma and palea. 2 n = 28. Plate 7A.
N.: throughout except in Bay of Plenty and Taranaki; S.: Nelson, and east of Main Divide; St.; Three Kings Is, Ch. Open forest and scrub, often on or near rock; occasionally a weed; from sea level to subalpine zone.
Endemic.
Specimens from Stewart Id (CHR 370996 Wilson 1981 and CHR 399109 Wilson & Meurk 1980) have very fine leaves, lemmas c. 3 mm and anthers c. 0.6 mm.
Specimens may have either wide, folded or flat leaves, and more obviously 5-nerved lemmas, or fine, filiform leaves, with the lateral lemma nerves scarcely visible. The two forms do not appear to be separated geographically, and plants growing as garden weeds in exposed dry situations have filiform leaves whereas those growing in shade have wider leaves. At sites of high fertility plants are very densely tufted and tussock-like with yellow-green leaves, erect to suberect inflorescences, and 4-5-flowered spikelets (B.P.J. Molloy, pers.comm.).
