Flora of New Zealand Series

Rhizomatous perennial with extravaginal branching, and much branched, multinoded stems of many cauline, often stiff hairy leaves, and often purpled spikelets on erectly branched narrow panicles. Branching extravaginal; rhizomes sometimes short; cataphylls chaffy. Leaf-sheath tight, short hairy or glabrous, overlapping node above, keel obscure. Ligule to 0.5 mm, finely erose, ciliate. Auricles 2, small, margin hairs (c. 3 mm) few. Collar short stiff hairy. Leaf-blade 5-25 cm × 2-5 mm wide, abaxially and adaxially abundantly stiff hairy sometimes more so abaxially, midrib prominent; margins with close-set, sharp teeth, retrorse below antrorse above, sometimes thickened, white, undulating. Culm to 85 cm, internodes many, glabrous, sometimes longitudinally grooved. Panicle 10-25 cm, narrow, slender, internodes short, branches erect to 5 cm, > internodes, rachis longitudinally grooved; branches and pedicels finely scabrid. Spikelets 25-35 mm, on slender finely scabrid pedicels; Ø lemmas often purple or purple-suffused. Glumes ± equal, 1-nerved, entire, often purple, margins ciliate, distant from Ø lemmas, < callus hairs; lower to 0.8 mm, upper to 1.5 mm. Callus 1-1.5-2 mm, clothed in hairs to 2 mm. Lower Ø lemma 12-20-30 mm, 5-7-nerved, scabrid, margin short (0.25 mm) hairy, awn > ½ lemma length; upper Ø lemma 17-26-35 mm, prickle-toothed throughout or glabrous below and prickled above, 5-7-nerved, awn > ½ lemma length; callus hairs 0. ⚥ lemma 5-7-9 mm, 5-7-nerved, shining, smooth except for teeth on upper ½ of keel, shortly awned (0.1-1.0 mm) from shortly lobed ciliate apex, margins hyaline; when cleistogamous often included by upper Ø lemma. Palea membranous, hyaline, produced into a mucro or becoming acute, apex ciliate; dimorphic, 4-6-8 mm in chasmogamous flowers, 2-3-4 mm in cleistogamous flowers. Lodicules 2, 1-2-2.7 mm in chasmogamous flowers occasionally hair-tipped, falling with caryopsis; 0 in cleistogamous flowers. Stamens 2-3-4; anthers 1.5-2.5-4.2 mm in chasmogamous flowers, (1)-2-3-4, 0.2-0.4-1.0 mm in cleistogamous flowers. Gynoecium: ovary 0.8-1.2 mm; stigma-styles 1.2-2.5-4.0 mm in chasmogamous flowers, 0.8-1.4-2.0 mm in cleistogamous flowers, stigma branches reaching ovary. Caryopsis laterally compressed, finely wrinkled, often falling free, 3.5-4.5-5.5 mm in chasmogamous flowers, 2-3.8-5.8 in cleistogamous flowers; embryo 0.6-1.0 mm. 2 n = 48.

N.: throughout; S.: throughout, less frequent in Canterbury, Otago and Westland, absent in Fiordland; St.; K.: Raoul Id; Ch. Open lowland forest and manuka-kanuka scrub, ruderal and in rough pasture; sea level to 1300 m.

Indigenous.

REPRODUCTIVE BIOLOGY

Chasmogamous and cleistogamous flowering are recognised in M. polynoda and M. stipoides (Connor and Matthews 1977 op. cit.) where cleistogenes are present sometimes at high frequency. Cleistogamy also occurs in aerially borne inflorescences of M. stipoides. There are no estimates of the frequencies in natural populations of chasmogamous and cleistogamous plants.

Dimorphism in lodicule, anther and palea lengths in M. polynoda and M. stipoides are described by Edgar and Connor (1998 op. cit.) as well as the frequencies of stamen number. There is an interspecific dimorphism for the distribution of stigmatic hairs on the style; stigmatic hairs reach to the base of the style in M. polynoda and M. stipoides but in M. avenacea and M. carsei the styles are naked below. The aspergilliform stigmas found in Ehrharta are unknown in Microlaena.

Also indigenous to Australia and Malesia.

There is every reason to believe that Australian plants are here as migrants, but it may be impossible to differentiate between them and indigenous plants; we are certain that M. stipoides var. breviseta Vickery, Telopea 1: 43 (1975), is not here.

Cleistogenes: Axillary single spikeleted cleistogenes occur regularly (Connor and Matthews 1977 op. cit.). Cleistogenes are smaller than aerial spikelets, asymmetrically grooved, awns 2-4 mm, lower Ø lemma = fertile lemma, vesture prominent only on main nerve; callus and callus hairs very small. Anthers as for cleistogamous flowers; stigma-styles shorter. Caryopsis as for cleistogamous flowers.