The New Zealand Plant Conservation Network

Species

Achnatherum petriei

Etymology

petriei: Named after Donald Petrei (1846 -1925), Otago botanist

Current Conservation Status

2018 - At Risk - Declining

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

2012 - At Risk - Naturally Uncommon
2009 - At Risk - Naturally Uncommon
2004 - Range Restricted

Qualifiers

2012 - EF, Sp
2009 - CD

Authority

Achnatherum petriei (Buchanan) S.W.L.Jacobs et J.Everett

Family

Poaceae

Flora Category

Vascular - Native

NVS Species Code

ACHPET

Structural Class

Grasses

Synonyms

Stipa petriei Buchanan

Distribution

Endemic. South Island only from South Canterbury to Central Otago

Habitat

Montane to subalpine (up to 1000 m a.s.l.). On dry stony ground and on rock outcrops (especially limestone and schist)

Features

Erect, wiry, yellow-green to brownish-grey perennial frequently branching at nodes. Branching extravaginal; cataphylls short. Leaf-sheath to 30 mm, usually glabrous, sometimes retrorsely pubescent. Ligule to 0.5 mm, auriculate, auricular lobes to 1 mm long, symmetrical or asymmetrical, usually finely pubescent. Collar thickened, occasionally with a very small tuft of hairs. Leaf-blade to 300 x 0.8 mm, narrow, involute, rigid, acicular, undersides glabrous, upper surface bearing short, stiff, white hairs. Culm to 600 mm long, wiry, internodes smooth, nodes purple, glabrescent. Panicle to 250 mm long, narrow; rachis smooth below, scabrid above, branches and pedicels scabrid. Glumes ± equal, to 7 mm long, hyaline, glossy, pink-suffused, produced into an awn-like process up to 0.5 mm long, or split at apex, < awn column; lower 1-nerved, upper 3-nerved. Lemma to 5.0 mm long, cylindrical, 3-5-nerved, margins contiguous, fulvous, clothed in white, ± appressed hairs; coma to 0.5 mm long, lobes short and inconspicuous; awn to 40 mm long, ± straight or weakly 1-geniculate, short and stiffly hairy, column loose twisted to 10 mm in length, arista to 30 mm long. Pale = lemma, clothed in long white hairs, apex ciliate, 2-nerved. Callus short (to 0.3 mm long), oblique, hairs white, to 1 mm long. Lodicules 3, one usually emarginate, or entire, 1-nerved, to 1 mm. Anthers to 2.7 mm long, weakly penicillate and shortly caudate. Seed 2.5-3.5 mm; hilum linear.

Similar Taxa

One of the five stipoid grass genera known in New Zealand. From the other four genera it is distinguished by the margins of the 3-nerved lemma contigious, by the persistent awn, and long hairs on the palea. From Achnatherum caudatum (Trin.) S.W.L.Jacobs et J.Everett it is distinguished by the extravaginal rather than intravaginal branching; by the upper surface of the leaf-blade clothed in hairs rather than finely prickle-toothed; by the glume nerves being obscure rather than conspicuous; by the completely hairy lemma (in A. caudatum the hairs are confined to the lemma keel and outer margin); by the minute, obscure rather than conspicuous coma; prominent long awn (40 cf. 20 mm long), and free flowering rather than mostly cleistogamous flowering habit.

Flowering

November - February

Fruiting

January - May

Propagation Technique

Easy from fresh seed and the division of whole plants. Requires full sun, and excellent drainage, on a fertile soil to grow well. Will not tolerate humidity or damp conditions.

Threats

Rather widespread but localised in its occurrences. Probably better qualifies as sparse because this is a naturally biologically sparse species. However, its survival now also depends on effective weed control. In some parts of its range it might be at risk from the spread of wild thyme (Thymus vulgaris L.) and stonecrop (Sedum acre L.).

Chromosome No.

2n = 42

Endemic Taxon

Yes

Endemic Genus

No

Endemic Family

No

Life Cycle and Dispersal

Floret dispersed by wind (Thorsen et al., 2009).

This page last updated on 29 Apr 2014