The New Zealand Plant Conservation Network

Species

Carex perplexa

Etymology

Carex: Latin name for a species of sedge, now applied to the whole group.
perplexa: From the Latin per (completely) and plectare (to entwine), referring to the entangled nature of the relationship among the species

Common Name(s)

Surville Cliffs 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 - Threatened - Nationally Critical
2004 - Threatened - Nationally Critical

Qualifiers

2012 - OL
2009 - CD, OL

Authority

Carex perplexa (Heenan et de Lange) K.A.Ford

Family

Cyperaceae

Flora Category

Vascular - Native

Structural Class

Sedges

Synonyms

Uncinia perplexa Heenan et de Lange

Distribution

Endemic. North Island, North Cape, Surville Cliffs, where it is only known from one small area of the 120 ha exposure of ultramafic rock.

Habitat

Ultramafic rock and talus in shaded sites under pohutukawa (Metrosideros excelsa Sol. ex Gaertn.) trees. Usually found growing with Carex ophiolithica de Lange et Heenan.

Features

Tufted sedge of ultramafic habitats forming large, spreading clumps. Culms 400-500 x 0.7-0.9 mm, glabrous, trigonous, > leaves; leaf-sheaths 30 mm or less, yellow-brown, nerves light brown. Leaves 6-11 per culm, 200-550 x 2-5 mm, weakly channelled, green; upper surface keeled, keel scabrid, margin scabrid, apex acute, trigonous, scabrid. Spikes linear, up to 55 mm long, 2-3 mm wide, usually subtended by 1 leaf-like bract 15-95 x 0.2-1.2 mm; female florets proximal, 15-24, internodes 3.5 mm long at spike base decreasing to 0.6 mm above; male florets distal, 15-20, overlapping. Male glumes 3.5-4 x 1 mm, narrow elliptic-lanceolate, light brown. Female glumes 3.5-4 x 1-1.2 mm, elliptic lanceolate to narrow elliptic, deciduous, light brown. Utricles 4.2-4.3 x 1.2-1.3 mm, planoconvex, ovate to elliptic, glabrous, light brown. Nuts 2.2-2.4 x 1-1.2 mm, oblong, light green to silver-green.

Similar Taxa

Carex perplexa appears to be most closely related to C. uncinata L.f.. This is a larger plant with longer spikes (up to 200 mm long), more female flowers per spike (60-120), and with larger fruits (utricles) and glumes. Carex uncinata, in common with all other New Zealand hook sedges except C. subtilis K.A.Ford and C. parvispica (which have 2n = 94,96 chromosomes respectively), has 2n = 88 chromosomes.

Flowering

December

Fruiting

January - April

Propagation Technique

Very easy from divisions of whole plants and from seed. However plants are slow growing and inclined to die unless fertilised frequently with a magnesium rich fertiliser.

Threats

Currently this species is confined to a single remnant stand of forest on the Surville Cliffs. This forest remnant is a survivor from past fires which all but destroyed the forest of the ultramafic zone at North Cape. Uncinia perplexa dislikes strong sun and so is vulnerable to the loss of the associated pohutukawa forest. The main threat to this forest is continuing browse from possums but fire is also a serious risk. Some weeds such as pampas grass (Cortaderia selloana (Schult. et Schult.f.) Asch. et Graebn.) and Hakea also pose a risk through potential competition should they become better established at North Cape.

Chromosome No.

2n = 132

Endemic Taxon

Yes

Endemic Genus

No

Endemic Family

No

This page last updated on 26 Aug 2015