Flora of New Zealand Series

; Holotype: CHR 227700! M. J. A. Simpson 6735 Mt Owen, Nelson, marble bluffs nth of Granity Pass, 22.1.1972.

Erect, often slender, usually reddish tufts, 12-65-(100) cm, with very lax, sometimes large panicles well overtopping the leaves; branching extravaginal. Leaf-sheath to 6 cm, sometimes reddish, glabrous to pubescent, margins often with longer hairs above. Collar with some long hairs. Ligule 0.2-0.6 mm, truncate, erose, glabrous to minutely or sometimes obviously ciliate. Leaf-blade 3-16 cm × 0.5-2-(6) mm, dull green to later reddish, flat, distinctly ribbed, abaxially smooth, often scabrid towards tip, adaxially minutely pubescent or minutely prickle-toothed on ribs; margins smooth or with very minute prickle-teeth. Culm 6-45-(70) cm, often geniculate at base, internodes glabrous. Panicle 3-20-(28) × 1-10 cm, lax, with very fine, spreading branches bearing individually evident or scarcely overlapping spikelets; rachis smooth below or with few prickle-teeth, more scabrid above, branches and pedicels with slightly denser long fine prickle-teeth. Spikelets 4.5-9 mm, light green to later brownish, usually red-tinged. Glumes very unequal in shape and size, ± hyaline, keels with minute close-set prickle-teeth in upper ½; lower c. ½, or rarely to ¾ or ≈ upper, very narrowly ovate almost subulate, subacute to acuminate, upper < spikelet, broadly ovate, subobtuse to obtuse, rarely acuminate or mucronate; margins entire. Lemma 4.5-7 mm, bicuspid, lower lemma smooth near base, papillose above and on keel, upper lemma(s) almost entirely papillose or minutely prickle-toothed, sometimes all lemmas equally smooth or equally scabrid; awn 5-9 mm, insertion in upper ¼ of lemma. Palea minutely prickle-toothed on upper ⅔ of keels, otherwise smooth. Callus hairs to 0.5 mm. Rachilla hairs to 1.3 mm. Lodicules to 1.3 mm, glabrous or ciliate. Anthers 0.8-1.5 mm. Gynoecium: ovary to 1 mm; stigma-styles to 1 mm. Caryopsis 2-3 × 0.5-0.6 mm. 2 n = 28. Fig. 10.

N.: south from Mt Hikurangi, the Volcanic Plateau, and Mt Egmont; S.: throughout.; St.; Ch. In open forest, scrub or tussock grassland, often on river or stream banks, and on calcareous rock; from near sea level to 1500 m but usually montane. FL Oct-Feb.

Endemic.

A plant with unusually contracted panicles but with glumes and lemmas matching those of T. lepidum was collected from Popotunoa, Otago by J. Buchanan, WELT 69040; other specimens from the same locality have the customary lax panicle, i.e. WELT 69042, WELT 69061.

The very lax panicles distinguish T. lepidum from other indigenous spp. with unequal glumes. The leaves and spikelets in T. lepidum are often tinged red, the lower lemma is usually smooth in the lower ½, and the glumes are usually very unequal in size and shape. Even when the two glumes are less disparate in length the difference in shape remains, with the lower glume very narrow-ovate and the upper broadly ovate.

Beuzenberg, E. J. and Hair, J. B. N.Z. J. Bot. 21: 14 (1983) made a single count from New Zealand Trisetum; they published the record under the name T. antarcticum but their voucher specimen, CHR 100118 [H. E. Connor] Tara Hills, Omarama, is T. lepidum.

Fig. 10 Trisetum lepidum S, spikelets, × 9; G 1, G 2, glumes, × 9; F, floret and rachilla, × 9; L, lemma lateral view, × 9; P, palea dorsal view, × 9; Lo, lodicules, × 24; O, ovary, styles and stigmas, × 24; St, stamens, × 24 © All rights reserved. [Image: 4X7D]