The New Zealand Plant Conservation Network

Species

Poa senex

Etymology

Poa: meadow grass

Common Name(s)

Old Man 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 - DP, RR
2009 - SP, RR

Authority

Poa senex Edgar

Family

Poaceae

Flora Category

Vascular - Native

NVS Species Code

POASEN

Structural Class

Grasses

Synonyms

None (first described in 1986)

Distribution

Endemic. New Zealand: South Island (Otago and Southland (Pisa, Old Man, Old Women, and Crown Ranges, also the Harris and Eyre Mountains).

Habitat

Alpine. On snow banks, in wet depressions, flushes, streamsides and other damp ground within alpine herbfield

Features

Diminutive, tufted, stoloniferous, glabrescent to glabrous, brownish green perennial grass, up to -250 mm tall, culms overtopping leaves; branching extravaginal; leaf-blades persistent. Leaf-sheath membranous, glabrous, ribbed, keeled. Ligule 0.5-1.5 mm, entire, tapered, glabrous throughout. Leaf-blade 10-35 × 1-2 mm, flat or folded, subcoriaceous, smooth, but midrib scabrid near curved tip; margins finely scabrid. Culm 30-200 mm, very slender, erect or geniculate at base, internodes glabrous. Panicle 10-30, ± open or contracted, with few, ovate spikelets; rachis, branches and pedicels slender with sparse, scattered prickle-teeth. Spikelets 2.0-3.5 mm, 2-3-flowered, light green, tinged purple. Glumes unequal, submembranous with hyaline margins, a few prickle-teeth on midnerve near tip; lower 1.5-2 mm, 1-nerved, narrow-lanceolate, acute, upper 2.0-2.5 mm, (1-)3-nerved, elliptic-oblong, subobtuse to obtuse. Lemma 2.0-2.5 mm, 5-nerved, elliptic-ovate, obtuse, glabrous, but midnerve with short crinkled hairs to c.½ length and sparsely prickle-toothed near tip, lateral nerves with a few hairs near base. Palea 1.5-1.8 mm, keels minutely scabrid, interkeel glabrous. Callus with a few wispy hairs. Rachilla c.0.5 mm, glabrous. Lodicules c.0.1 mm. Anthers 0.3-0.4 mm. Ovary 0.4-0.5 mm; stigma-styles 0.8-1 mm. Seeds c.1.0 × 0.5 mm

Similar Taxa

Allied to P. sublimis Edgar and P. incrassata Petrie, two other species which are diminutive, small-anthered, alpines colonising damp ground. From these species Poa senex differs in having hairs on the lemma nerves. From P. sublimis it is further distinguished by the more contracted panicle with firmer branchlets, and from P. incrassata by the wider leaves, and by the flat, not hooded, lemma tip and glabrous, not papillose, lemma internerves.

Flowering

November - December

Fruiting

December - March

Propagation Technique

Difficult. Can be grown from fresh seed and rooted pieces in an alpine house. Will not flower or thrive in warm or humid climates. Intolerant of drying out.

Threats

Not Threatened. Listed because it is a Naturally Uncommon, Biologically Sparse, Range Restricted Alpine endemic.

Chromosome No.

2n = 28

Endemic Taxon

Yes

Endemic Genus

No

Endemic Family

No

This page last updated on 7 Jan 2014