The New Zealand Plant Conservation Network

Species

Carex obtusifolia

Etymology

Carex: Latin name for a species of sedge, now applied to the whole group.
obtusifolia: with a blunt leaf

Common Name(s)

Fine-leaved Bastard Grass

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 - Not Threatened
2004 - Not Threatened

Qualifiers

2012 - Sp

Authority

Carex obtusifolia (Heenan) K.A.Ford

Family

Cyperaceae

Flora Category

Vascular - Native

NVS Species Code

UNCOBT

Structural Class

Sedges

Synonyms

Uncinia obtusifolia Heenan

Distribution

Endemic. New Zealand: North, South and Stewart Islands. In the North Island found only in the mountainous regions of the southern half; in the South Island present mainly west of the main divide (rarely in the east). Found throughout Stewart Island.

Habitat

Wet ground in bogs, damp flushes, hollows, and seepages in tussock grassland, around the margins of clearings, among open scrub, and in open pasture in lowland and low-alpine areas.

Features

Small tufts to small tussocks, laxly to densely caespitose, sometimes with fine creeping rhizomes. Culms glabrous, trigonous, at flowering similar in length to leaves, at maturity much longer than leaves, 50-400 × 0.3-0.6 mm; basal bracts light brown to yellow-brown, dull, 2-7 mm long. Leaves plano-convex or concavo-convex, rigid, linear, strongly nerved on abaxial surface, erect or ascending, 45-300 × 0.4-0.5 mm; apex obtuse and nerves weak or absent; margins scabrous when young, often becoming glabrous when mature. Spikes oblong, 15-20 mm long; female flowers proximal, 3-7, internodes 1.5-3.0 mm long; male flowers distal, 3-5. Glumes < utricle, deciduous, elliptic-lanceolate to lanceolate, 3.5-5.0 × 1.5-2.0 mm; midrib green; apex subacute to obtuse; margins membranous. Utricles trigonous, elliptic to lanceolate, yellow-green, yellow-brown, or light brown, lateral nerves present but not conspicuous, 5.0-6.2 × 0.9-1.1 mm; stipe and beak both narrow, each c. 1.5 mm long; rachilla exserted beyond utricle, 5.3-6.5 mm long. Nut trigonous, narrow-elliptic to linear, pale brown, dull, 3.0-3.9 × 0.8-1.1 mm

Similar Taxa

Previously included within the allied Carex cheesemanniana (Boeckeler) K.A.Ford from which it differs by its much finer (almost capillary) narrower leaves, culms, spikes, and utricles. The utricles are yellow-brown rather than dark brown; and unlike Carex cheesemanniana the glumes are smaller and shorter than the utricle, further the floret internodes are longer than in C. cheesemanniana. The nuts of Carex obtusifolia are narrower and longer than those of C. cheesemanniana. It could also be confused with the forest dwelling Carex lectissima K.A.Ford. That species is distinguished from all other New Zealand Uncinia by the light-coloured striations on the red-brown basal sheaths, and from Carex obtusifolia by the trigonous upper part of the leaf and by the acute rather than obtuse leaf apex.

Flowering

November - December

Fruiting

December – May

Propagation Technique

Unknown. However like Carex debilior it is probably easily grown from fresh seed and by the division of established plants. It probably requires a permanently damp, peaty soil and semi-shaded conditions.

Threats

Not Threatened

Chromosome No.

2n = 88

Endemic Taxon

Yes

Endemic Genus

No

Endemic Family

No

This page last updated on 26 Aug 2015