The New Zealand Plant Conservation Network

Species

Poa acicularifolia subsp. ophitalis

Etymology

Poa: meadow grass

Common Name(s)

Ultramafic Cushion Poa

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

Poa acicularifolia subsp. ophitalis Edgar

Family

Poaceae

Flora Category

Vascular - Native

Structural Class

Grasses

Synonyms

None (first described in 1986)

Distribution

Endemic. New Zealand: South Island (eastern Nelson and western Marlborough).

Habitat

Subalpine. An ultramafic endemic confined to ultramafic soil and scree

Features

Small, tufted blue-green perennial with tufts usually aggregated or with rhizomes interconnecting to form loose mats. Plants 100-200 mm at flowering with culms far overtopping leaves, arising from a woody, much-branched rhizome, with wiry, very long-creeping roots at nodes and numerous fine rootlets; branching intravaginal; leaf-blades disarticulating at ligule. Leaf-sheath light cream to later greyish brown, much wider than leaf-blade, glabrous, membranous, sparsely ribbed; margins very wide hyaline. Ligule 1-5 mm, apically glabrous, tapered, entire, abaxially scabrid near base or smooth, occasionally extending as a rim-like membranous contra-ligule. Leaf-blade 5.0-25.0 x c.0.5 mm, involute, erect, firm, rigid, glabrous; margins sparsely prickle-toothed, slightly narrowed to firm abruptly shortly curved, sometimes pungent tip. Culm 30-150 mm, with 1-2 small cauline leaves, internodes glabrous. Panicle 15-35 mm, lax; rachis glabrous, branches capillary, smooth or very finely scabrid, with 1-2 spikelets at branchlet tips. Spikelets 4-8 mm, 2-5-flowered, light grey-green. Glumes subequal, 2.0-3.5 mm, 3-nerved, elliptic-ovate, midnerve scabrid near subobtuse tip, margins often finely scabrid. Lemma 3-4 mm, 5-nerved, oblong-elliptic, obtuse, short-pubescent throughout lower 1/3 to 1/2 but central internerves sometimes glabrous, scabrid above on midnerve and occasionally towards tip; margins scabrid above. Palea 2.5-3.5 mm, keels ciliate-scabrid, interkeel minutely hairy on lower 1/2. Callus ringed by short soft hairs. Rachilla 0.5-1 mm, usually ciliate; prolongation twice as long. Lodicules 0.5 mm. Anthers 1.8-3 mm. Seeds c.1.5-2 x 0.5 mm.

Similar Taxa

Most likely to be confused with Poa colensoi Hook.f., which is a highly variable species. The P. colensoi form present on ultramafic substrates differs from P. acicularifolia subsp. ophitalis by the scabrid rather than smooth upper leaf-blades, and short-hairy rather than almost glabrous or shortly scabrid lemmas. Poa acicularifolia Buchanan subsp. acicularifolia is confined to calcareous substrates and differs by its tightly compact, mat-forming growth, and shorter, rigid, cartilaginous, falcate leaves

Flowering

October - December

Fruiting

December - March

Propagation Technique

Easily grown in a small pot in an alpine house. Resents humidity and does best in free draining, base-rich soils.

Threats

An ultramafic endemic which is naturally restricted to small areas of suitable habitat within the subalpien zone of this rock type. There are currently no known threats to this grass.

Chromosome No.

2n = 28

Endemic Taxon

Yes

Endemic Genus

No

Endemic Family

No

This page last updated on 7 Jan 2014