The New Zealand Plant Conservation Network

Species

Trisetum lasiorhachis

Etymology

Trisetum: Three-bristled

Current Conservation Status

2012 - Not Threatened

Conservation status of New Zealand indigenous vascular plants, 2012
The conservation status of all known New Zealand vascular plant taxa at the rank of species and below were reassessed in 2012 using the New Zealand Threat Classification System (NZTCS). This report includes a statistical summary and brief notes on changes since 2009 and replaces all previous NZTCS lists for vascular plants. Authors: Peter J. de Lange, Jeremy R. Rolfe, Paul D. Champion, Shannel P. Courtney, Peter B. Heenan, John W. Barkla, Ewen K. Cameron, David A. Norton and Rodney A. Hitchmough. File size: 792KB

Previous Conservation Status

2009 - Not Threatened
2004 - Not Threatened

Authority

Trisetum lasiorhachis (Hack.) Edgar

Family

Poaceae

Flora Category

Vascular - Native

Structural Class

Grasses

Synonyms

Trisetum antarcticum var. lasiorhachis Hack.

Distribution

Endemic. North Island only, mainly in subalpine to alpine portions of the Central North Island and adjacent main axial ranges. Also collected on Mt Pirongia, and in the past from near Waiuku and Mt Wellington, Auckland. It is now extinct at these last two locations.

Habitat

Usually a montane to subalpine species (600-1500 m a.s.l.) but occasionally found at lower altitudes. May be found growing in scrub, open forest, tussock grassland, along river and stream sides, and on rock outcrops

Features

Stout, erect to somewhat lax, narrowly tufted, greyish green, glaucous to dull green grass 50-850 mm tall, sometimes rhizomatous, with pale straw-coloured leaf-sheaths. Leaf blades usually bearing scattered long, pilose hairs, with pilose hairs on culms and with the panicle-rachis and branches usually pubescent. Branching extravaginal. Leaf-sheath to 60 mm long, pubescent. Collar hairs sparse, pilose, long. Ligule 0.3-0.8 mm, truncate, erose, glabrous or ciliate. Leaf-blade 50-250 x 1.3-3.0 mm, flat, rarely inrolled and narrower, often with scattered long hairs, undersides prickle-toothed toward apex, upper surface ribbed with more or less scattered minute prickle-teeth or short hairs on ribs; margins minutely prickle-toothed, and often bearing scattered long pilose hairs. Culm 100-500 mm, internodes pilose above and below nodes, densely pilose, pubescent or glabrous towards panicle. Panicle 30-210 x 10-50 mm, lanceolate, usually open with visible rachis but spikelets clustered and individually inconspicuous; rachis, branches, and pedicels densely pilose to sparsely, minutely hairy. Spikelets 5-8 mm, pale green or purple-tinged. Glumes unequal, keels often strong, prickle-toothed in upper 1/2 or almost throughout; lower 2/3-4/5 length of upper, narrow-oblong, tapered to an often long-acuminate apex, upper < spikelet, elliptic, acute to shortly acuminate; margins almost entire with very few prickle-teeth near apex. Lemma 5.0-7.5 mm, bicuspid, minutely prickle-toothed or papillate; awn 5.0-9.5 mm, straight to later recurved, insertion point in upper 1/2 to 1/3 of lemma. Palea minutely prickle-toothed on keels and margins. Callus hairs to 0.8 mm. Rachilla hairs to 2 mm. Lodicules c.1.3 mm, glabrous. Anthers 1.8-22. mm. Ovary to 1 mm long; stigma-styles to 2.4 mm. Seed 2.5 x 0.8 mm.

Similar Taxa

Closest to T. serpentinum Edgar et A.P.Druce with which it shares distinctly hairy culms and leaves. However, T. lasiorhachis does not grow on ultramafic substrates. While Trisetum serpentinum is characteristically reddish-green, T. lasiorhachis is green to grey-green. In T. serpentinum the lemma is 3.0-4.5 mm long, the awns less than or equal to the lemma; the leaf-blade inrolled, < 1 mm diameter, only very rarely flat and up to 2 mm wide. In T. lasiorhachis the lemma is 5.0-7.5 mm long; the awn is much greater than of equal to the lemma; the leaf-blade is usually flat (rarely inrolled), and 1.3-3.3 mm wide. T. lasiorhachis is known only from the North Island, while T. serpentinum is occurs in both the North and South Islands,.

Flowering

November - February

Fruiting

January - May

Propagation Technique

Easy from fresh seed and rooted pieces but will not thrive in humid climates. Does best in damp soil, in a cool spot with plenty of air movement

Threats

Not Threatened

Chromosome No.

2n = 28

Endemic Taxon

Yes

Endemic Genus

No

Endemic Family

No

This page last updated on 20 Jan 2014