The New Zealand Plant Conservation Network

Species

Rytidosperma telmaticum

Etymology

Rytidosperma: wrinkled seed

Common Name(s)

tarn bristle grass

Current Conservation Status

2012 - 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

2009 - Threatened - Nationally Vulnerable
2004 - Not Threatened

Qualifiers

2012 - DP, RR
2009 - DP, EF, RR

Authority

Rytidosperma telmaticum Connor et Molloy

Family

Poaceae

Flora Category

Vascular - Native

Structural Class

Grasses

Synonyms

None

Distribution

Endemic. South Island only, inland from mid Canterbury, the MacKenzie Country and from one site at Conroys Road, Alexandra, Central Otago

Habitat

A species of intermontane basins where it grows on the margin of kettleholes, tarns and small ponds.

Features

Small low-growing olive-green tufted tussock-forming, self-compatible grass becoming pallid with many old small straw-coloured bladeless ligule-tipped sheaths below compact intravaginal innovations of 3-4 semi-pungent leaves much less than culms; sometimes open and evidently stoloniferous, rooting and shooting at nodes. Leaf-sheath 5-10 mm, usually glabrous but often long hairy, pale straw-coloured, shining, ridged, broader than leaf blade; upper surface with many fine hairs; apical tuft 0.50-0.75 mm, sparse, spreading. Ligule 0.2-0.3 mm, of fine hairs. Leaf-blade 10-25 x 2 mm, inrolled, glabrous, apex thickened and pointed, ciliate; disarticulating at ligule; undersides very finely prickle-toothed on nerves; margins very finely antrorsely prickle-toothed. Culm 20-200 mm, internodes smooth, shining; nodes 3-5, constricted, often geniculate below; inflorescence internodes 30-70 mm long, sheath sometimes with regular horizontal bands. Inflorescences racemose or a racemose-panicle 5-35 mm, bearing 2-7 spikelets on very short branches or solitary; margins of rachis and branches very finely toothed; pedicels hairy, hairs denser and longer below spikelets. Spikelets 4-5 mm, of 3-5 small closely compact florets usually included by glumes, occasionally upper florets exserted. Glumes c. 4-5 mm long, linear acute, faintly keeled, keels occasionally scabrid above, centrally purple or green, margins chartaceous, 3-5-nerves confluent above and central nerve excurrent; upper surface bearing abundant small white hairs. Lemma 1.50-1.75-2.25 mm, ovate, straw-coloured, sometimes purpled above, 5-7 nerves anastomising below sinus; dense long hairs in two rows less than or equal to lemma apex, upper row of irregular tufts, lower row of denser longer tufts reaching upper row, glabrous below lower row, single pair of marginal tufts at level of rhacilla apex often extending below, upper surface finely hairy; apex tridentate with two 0.2 mm long lateral lobes and finely ciliate mucro in sinus, 0.2-0.5 mm or absent, usually > lobes. Callus 0.10-0.25 mm, rounded-obtuse, disarticulation oblique, marginal hair tufts 0.3-0.5 mm overlapping lower lemma hairs. Rachilla 0.3-0.7 mm, glabrous. Anthers 0.30-0.75 mm, purple. Ovary 0.4-0.5 mm, stipitate; stigma-styles 0.75-1.00 mm. Seed 0.8-1.0 mm, stipitate, broadly ovate.

Similar Taxa

Allied to Rytidosperma pumilum from which it differs by its two rows of conspicuous hairs on the lemma, and by its shorter, rounder callus covered in long hairs.

Flowering

November - February

Flower Colours

Violet / Purple

Fruiting

January - May

Propagation Technique

Easily grown from fresh seed and by division of whole plants. Best kept in a pot, that is partially submerged in water and placed in the full sun. Dislikes humid conditions.

Threats

Changes to the hydrologic regime of the intermontane basins in which this species mostly occurs, caused by recent (2005 +) changes in local agricultural practises, are resulting in increasingly longer periods of dry conditions. This is favouring the spread of weeds which in turn are outcompeting the indigenous turf vegetation in which this species grows. On going deterioration of these habitats means that this species and many of its associates are probably under serious threat of extinction over large parts of their range.

Chromosome No.

2n = 24

Endemic Taxon

Yes

Endemic Genus

No

Endemic Family

No

This page last updated on 31 Jul 2014