Species

Gahnia procera

Etymology

Gahnia: after Gahn
procera: long (filaments)

Common Name(s)

giant sedge, Gahnia, mountain Gahnia

Current Conservation Status

2012 - Not Threatened

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

Authority

Gahnia procera J.R.Forst. et G.Forst.

Family

Cyperaceae

Flora Category

Vascular - Native

NVS Species Code

GAHPRO

The National Vegetation Survey (NVS) Databank is a physical archive and electronic databank containing records of over 94,000 vegetation survey plots - including data from over 19,000 permanent plots. NVS maintains a standard set of species code abbreviations that correspond to standard scientific plant names from the Ngä Tipu o Aotearoa - New Zealand Plants database.

Structural Class

Sedges

Synonyms

None

Distribution

Endemic. North, South and Stewart islands. In the North Island known from the Coromandel Peninsula south of which it is mostly confined to the main axial ranges. In the South Island confined to the wetter western areas of Nelson, Westland and Fiordland with rare extensions east into Marlborough and Canterbury. Found throughout Stewart Island.

Habitat

Montane to subalpine (up to 1300 m a.s.l.). Usually in forest and subalpine scrub. Mostly in cool, shaded sites on peat but at higher altitudes and in cloud forest it often grows in more open sites, in boulder field, on rubble slopes, on cliff faces and on the margins of mires and bogs in subalpine scrub.

Features

Robust tussock forming perennial sedge. Tufts arising from a short rootstock. Culms 0.3-1.2 m, 2-4 mm diameter. Leaves numerous, = or > culms, densely crowded at base of culm; lamina up to 1.2 m long, dark green above somewhat paler and often glaucous beneath, narrowly linear, glabrous above, margins flat or recurved otherwise strongly involute when dry, smooth at base, scabrid towards apex; sheaths dull brown, up to 180 mm long. Panicle immersed within foliage, 200-600 x 25-50 mm, more or less drooping, branchlets often in more or less distant clusters. Spikelets 1(-2)-flowered, 9-14 mm long, on slender peduncles or more or less sessile. Glumes 4-5, purple-black, the 2-3 outer glumes empty, lanceolate with a long scabrid awn, the inner 1-2 shorter, deeply concave. Stamens 4-6. Style-branches 4(-5). Nut 5.0-6.5 x 2.0-2.5 mm, brownish orange, or rarely cream, smooth and glossy, ovoid to elliptic-ovoid, occasionally slightly grooved, apex darker, obtuse, rarely scaberulous, wider than the short persistent style-base; endocarp distinctly transversely grooved within.

Similar Taxa

Of all the Gahnia species G. procera is most likely to be confused with Gahnia pauciflora which has a similar stature and can grow in similar habitats. From that species G. procera is distinguished by the inflorescences which are usually hidden amongst the foliage rather than towering over it, and by the purple-black glumes with lower sterile glumes > the upper fertile glumes. The nut of G. procera is ovoid to elliptic-ovoid, uniformly coloured brownish-orange (rarely cream) with the tip only slightly darker, while those of G. pauciflora are fusiform, brownish-orange or yellow-cream, with the tip consistently pigmented black. Morelotia affinis (Brong.) Blake although superficially similar is a much smaller plant of lower altitudes whose glumes are spirally rather than distichously arranged.

Flowering

December - February

Fruiting

Fruit may be found throughout the year

Propagation Technique

Difficult to culivate. Best results are achieved with seed sown into untreated saw dust. Plants resent root disturbance and usually die if transplanted. Despite these problems this is an attractive species well worth attempting to grow. Once established it flourishes in a range of conditions but does best in partial shade in a damp, humus-enriched but well drained soil.

Threats

Not Threatened

Endemic Taxon

Yes

Endemic Genus

No

Endemic Family

No

Life Cycle and Dispersal

Florets are wind dispersed (Thorsen et al., 2009).

Attribution

Fact Sheet prepared by P.J. de Lange (30 October 2005). Description adapted from Moore and Edgar (1970)

References and further reading

Gardner, R.O. 1996. Gahnia pauciflora and G. procera and a note on G. lacera. Auckland Botanical Society Journal, 51: 7-10.

Moore, L.B.; Edgar, E. 1970: Flora of New Zealand. Vol. II. Government Printer, Wellington.

Thorsen, M. J.; Dickinson, K. J. M.; Seddon, P. J. 2009. Seed dispersal systems in the New Zealand flora. Perspectives in Plant Ecology, Evolution and Systematics 11: 285-309

This page last updated on 20 Nov 2015