The New Zealand Plant Conservation Network

Species

Poa acicularifolia subsp. acicularifolia

Etymology

Poa: meadow grass

Common Name(s)

Limestone 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

Authority

Poa acicularifolia Buchanan subsp. acicularifolia

Family

Poaceae

Flora Category

Vascular - Native

NVS Species Code

POAASA

Structural Class

Grasses

Synonyms

Poa acicularifolia Buchanan

Distribution

Endemic. New Zealand: Marlborough, North and Central Canterbury

Habitat

Montane to subalpine grassland overlying calcareous rocks and soils. Also on limestone bluffs and screes

Features

Small, blue-green perennial grass forming diminutive, compact, tight, interlacing mats, 100-150 mm at flowering. 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 stiff, rigidly cartilaginous, falcate, 5.0-25.0 × c.0.5 mm diameter, involute, glabrous; margins sparsely prickle-toothed, slightly narrowed to firm abruptly shortly curved, sometimes pungent tip. Culm 30-100 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 ½ 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 ½. 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.1.5-2.0 × 0.5 mm.

Similar Taxa

Most likely to be confused with Poa colensoi Hook.f., which is a highly variable species. The most common form of P. colensoi present in the north eastern South Island differs from P. acicularifolia subsp. ophitalis by the longer, erect, firm rather than rigidly cartilaginous falcate leaves, scabrid rather than smooth upper leaf-blades, and short-hairy rather than almost glabrous or shortly scabrid lemmas. Poa acicularifolia Buchanan subsp. ophtalis is confined to ultramafic substrates in eastern Nelson and differs by its more open, rather loosely interconnected rather than tightly compact mat-forming growth habit, and longer, less rigid, erect rather than falcate leaves.

Flowering

October - December

Fruiting

November - April

Propagation Technique

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

Threats

Potentially threatened by the spread of hawkweeds (Hieraceum spp.) and grasses (such as cocksfoot (Dactylis glomeratus L.) onto the limestone habitats it favours. At present there is no documented evidence of decline but careful monitoring is needed at key sites to be sure this grass remains secure. Current observations (which lack hard data) suggest it still exists as stable populations within its main known habitats.

Chromosome No.

2n = 28

Endemic Taxon

Yes

Endemic Genus

No

Endemic Family

No

This page last updated on 7 Jan 2014