The New Zealand Plant Conservation Network

Species

Trisetum serpentinum

Etymology

Trisetum: Three-bristled
serpentinum: refers to a snake

Current Conservation Status

2012 - At Risk - Naturally Uncommon

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 - At Risk - Naturally Uncommon
2004 - Range Restricted

Qualifiers

2012 - RR, Sp

Authority

Trisetum serpentinum Edgar et A.P.Druce

Family

Poaceae

Flora Category

Vascular - Native

Structural Class

Grasses

Synonyms

None

Distribution

Endemic. North and South Islands only. In the North Island known only from the Surville Cliffs, North Cape. In the South Island confined to the ultramafic mineral belt of DUrville Island, Mt Dun, and the Red Hills

Habitat

Confined to Ultramafic soils and rock exposures where it usually grows on open ground or mixed in with other short grasses. Occasionally on cliff faces

Features

Dark green, red-green to red, diffuse, tufted grass up to 800 mm tall. Leaves narrow, inrolled, overtopped by narrow to somewhat lax, purplish to maroon panicles. branching extravaginal. Leaf-sheath 10-40 mm, softly pubescent, with longer scattered hairs on sheaths of culm-leaves, often also on margins. Ligule 0.4-0.8 mm, erose, minutely ciliate. Leaf-blade 20-160 mm, inrolled, rarely not, < 1 mm diameter, up to 2 mm wide, often with scattered long hairs, undersides smooth or with fine prickle-teeth on ribs; margins minutely prickle-toothed, often with scattered long hairs. Culm 80-460 mm long, slender, internodes with long fine hairs above nodes, and with a small band of shorter hairs below nodes, uppermost node consistently glabrous. Panicle 20-100 x 5-20 mm, narrow-lanceolate to elliptic, sometimes open, with visible rachis and short ascending to spreading branches bearing clustered spikelets; rachises and branches with moderately dense, fine prickle-teeth and often a few longer hairs at lower nodes of rachis and at base of panicle. Spikelets 4-6.5 mm, purple or maroon. Glumes unequal, with sparse short prickle-teeth on keel; lower 2/3-3/4 length of upper, oblong-lanceolate, upper < to more or less equivalent in length of spikelet, elliptic-lanceolate; margins with very few minute prickle-teeth near acute to acuminate apex. Lemma 3.0-4.5 mm, bicuspid, minutely-papillose; awn 3-4 mm, usually recurved, insertion point in upper quarter of lemma. Palea minutely prickle-toothed on keels and margins. Callus hairs 0.2 mm. Rachilla hairs to 0.8 mm. Lodicules to 1 mm, glabrous. Anthers to 1.5 mm long. Ovary to 0.8 mm; stigma-styles to 1 mm. Seed not seen.

Similar Taxa

Closest to T. lasiorhachis (Hack.) Edgar with which it shares distinctly hairy culms and leaves. However, as the name implies T. serpentinum is endemic to ultramafic substrates. A habitat from which T. lasiorhachis is absent. Trisetum serpentinum is characteristically reddish-green, T. lasiorhachis 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. Trisetum serpentinum is known from the North and South Islands, T. lasiorhachis only from the North Island.

Flowering

October - February

Fruiting

December - May

Propagation Technique

Easy from fresh seed and rooted pieces but difficult to maintain in cultivation. Does best in a pot.

Threats

Not directly threatened, however, it is confined to ultramafic rock and soils, and in some of these locations it can be very uncommon

Chromosome No.

2n = 28

Endemic Taxon

Yes

Endemic Genus

No

Endemic Family

No

This page last updated on 20 Jan 2014