Flora of New Zealand Series

≡Diplax polynoda Hook.f., Fl. N.Z. 1: 290 (1853)

≡Ehrharta multinoda F.Muell., Fragm. 7: 90 (1870) nom. illeg.; 

Lectotype: K! Colenso 1557 N. Zealand [base of Ruahine Range] (designated by Edgar and Connor 1998, op. cit. p. 580). =

Microlaena ramosissima Colenso, T.N.Z.I. 21: 105 (1889); 

Lectotype: WELT 21966! W. Colenso Dannevirke H.B. (designated by Edgar and Connor 1998 op. cit. p. 580).

Scrambling, bambusiform, rhizomatous perennial with stout, bare internodes below but leafy above, emitting cataphyll-surrounded shoots at rhizome and at nodes; inflorescence short, infrequent; cleistogenes common along stems. Leaf-sheath keeled, glabrous, < culm internodes, margins membranous, apex with conspicuous tufts of hairs 1.5-3-5 mm sometimes absent. Ligule 0.2-0.3-0.5 mm, erose, ciliate. Auricles 0. Collar thick, fringed by some hairs from sheath apex. Leaf-blade 10-30 cm × 2-5 mm wide, becoming long and fine, midrib evident, glabrous; margins scabrid, prickles spaced throughout but fewer below. Culms to 1.5 m × 2-2.5 mm diam., many noded, glabrous or hairy, or densely long hairy below nodes, longitudinally grooved. Inflorescence a narrow raceme 6-19 cm, internodes short, 3-10 solitary spikelets, or panicle to 15 cm of short and long branches at nodes, > internodes, up to 20 spikelets; rachis densely hairy at nodes sometimes throughout, branches and pedicels hairy. Spikelets 14-17 mm, on short or long pedicels. Glumes unequal, 1-nerved, occasionally bifid, margins and apex ciliate; lower 0.5-1-2 mm, ≤ callus hairs, upper 2-3-5 mm, > callus hairs. Lower Ø lemma 8-11-15 mm, 3-5-nerved, finely prickle-toothed, margin shortly (0.5-0.75 mm) hairy; adaxially finely hairy, awn < ⅕ lemma length; callus hairs 0.5-1.0 mm; upper Ø lemma 12-14-18 mm, 5-7-nerved, keel prickle-toothed, margin ciliate, finely prickle-toothed, awn < ½ lemma length; callus hairs few. ⚥ lemma 6-7.5-10 mm, 5-7-nerved, awn 0 or 0.3-0.5 mm from shortly lobed ciliate apex, finely prickle-toothed above, glabrous below, keel toothed. Palea 4.5-5.5-6.5 mm, membranous, becoming acute; keel, upper margins and apex long ciliate. Lodicules 2, 0.8-1.0-1.75 mm, irregularly lobed or entire, sometimes hair-tipped. Stamens 4; anthers 1.0-2.5-4.5 mm, yellow. Gynoecium: ovary 0.7-1.3 mm; stigma-styles 1.0-2-3.5 mm, stigmatic branches to apex of ovary. Caryopsis 3-4.5-5.5 mm; embryo 1 mm. 2 n = 48. Chasmogamous and cleistogamous.

N.: Northland, offshore islands; central and eastern regions; S.: Nelson and in east from Marlborough, to Otago Peninsula but sporadic. Forest, scrub and rocky bluffs; sea level to 400 m.

Endemic.

Willemse (1982 op. cit.) compared M. polynoda with M. stipoides var. breviseta Vickery of Australia to which it bears no resemblance; M. polynoda is not a name "of doubtful application" as Willemse thought. This comment by Clayton and Renvoize (1986 op. cit. p. 77) is perplexing: "Cleistogenes occur in E. stipoides [Connor, H. E. and Matthews, B. A. N.Z. J. Bot. 15: 531-534 (1977)], where they have been mistaken for a distinct species".

This species has sometimes been confused with the endemic Anemanthele lessoniana (Stipeae) which is also bambusiform in its habit.

Cleistogenes: Axillary cleistogenes in swellings at culm nodes are common - as many as seven at consecutive nodes - and preclude the possibility of axillary branches forming there. Cleistogenes are longer than aerial spikelets. Glumes, or bracts, 1 or 2, subtend the asymmetrically grooved or flattened spikelet. There are no basal hairs. Lower Ø lemma 10-14-20 mm, awned, shining, smooth except for teeth on keel; upper Ø lemma 10-15-20 mm awned, shining, glabrous. ⚥ lemma 7-9.5-12 mm, shining, glabrous, awned. Palea 4.5-5.5-7 mm, narrow, hyaline, ciliate, sometimes adherent to caryopsis. Lodicules absent. Stamens 2-(3-4); anthers 0.4-0.7-1.3 mm. Gynoecium: ovary 1.0 mm; stigma-styles 1.5-2.5-2.8 mm. Caryopsis 2.8-5.5-7.0 mm, longer than in aerial flower. Pollen germinates in the loculi and pollen tubes grow out onto the stigmatic branches. Details are in Connor and Matthews (1977 op. cit.). Hubbard, C. E. Icon. Pl. (5th Series) 3: t. 3209 (1930) had recorded the cleistogenes much earlier almost as an aside to his description of Cleistochloa subjuncea. Specimens in cultivation of Marlborough Sounds provenance produced both aerial chasmogamous flowers and cleistogenes, as did plants from the Rakaia Gorge, Canterbury.

On some specimens only cleistogenes are present. For further discussion see Schoen, D. J. Amer. J. Bot. 71: 711-719 (1984) and Schoen, D. J. and Lloyd, D. G. Biol. J. Linn. Soc. 23: 303-322 (1984), and for a commentary see Connor, H. E. in Soderstrom, T. R. et al. (Eds) Grass Systematics and Evolution (1987).