Wire rush, lesser wire rush
Calorophus minor Hook.f.; Calorophus elongatus var. minor Hook.f.; Hypolaena lateriflora var. minor (Hook.f.) Cheeseman
Vascular – Native
Rushes & Allied Plants
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.
2n = 24
Current conservation status
The threat classification status of all known New Zealand vascular plant taxa at the rank of species and below were reassessed in 2017 using the New Zealand Threat Classification System (NZTCS) – more information about this can be found on the NZTCS website This report includes a statistical summary and brief notes on changes since 2012 and replaces all previous NZTCS lists for vascular plants. Authors: By Peter J. de Lange, Jeremy R. Rolfe, John W. Barkla, Shannel P. Courtney, Paul D. Champion, Leon R. Perrie, Sarah M. Beadel, Kerry A. Ford, Ilse Breitwieser, Ines Schönberger, Rowan Hindmarsh-Walls, Peter B. Heenan and Kate Ladley. Please note, threat classifications are often suggested by authors when publications fall between NZTCS assessment periods – a suggested threat classification status has not been assessed by the NZTCS panel.
2017 | Not Threatened | Qualifiers: SO
Previous conservation statuses
2012 | Not Threatened
2009 | Not Threatened
2004 | Not Threatened
Indigenous. New Zealand: North, South and Stewart Islands. From the Central Volcanic Plateau south in upland areas. Throughout the South Island but scarce in Marlborough and north Canterbury. Also Australia.
Coastal to alpine (up to 1350 m a.s.l.). The dominant peat-forming species of low moor and high moor (raised bogs), oligotrophic, ombrotrophic wetland systems in New Zealand (montane to alpine in the North Island). Tolerates extremely acidic conditions (up to pH 2.5).
Wetland plant indicator status rating
Information derived from the revised national wetland plant list prepared to assist councils in delineating and monitoring wetlands (Clarkson et al., 2021 Manaaki Whenua – Landcare Research Contract Report LC3975 for Hawke’s Bay Regional Council). The national plant list categorises plants by the extent to which they are found in wetlands and not ‘drylands’. The indicator status ratings are OBL (obligate wetland), FACW (facultative wetland), FAC (facultative), FACU (facultative upland), and UPL (obligate upland).
OBL: Obligate Wetland
Almost always is a hydrophyte, rarely in uplands (non-wetlands).
Dioecious, perennial herb producing numerous, branched, flexuose culms collectively forming densely interwoven tangles. Rhizome rather robust for plant, erect, up to 8 mm diameter, covering with light brown, imbricating scale-like sheaths and very thick tufts of brown hairs; roots numerous, mostly horizontal-ascending rather than descending, 1-1.5 mm diameter, densely covered in pinkish-white root hairs. Culms 0.012-0.81 m, 0.7-1.3 mm diameter, much-branched, flexuous, terete or slightly flattened and grooved on one side, glabrous, dark green to dark brown, erect when short, otherwise more or less prostrate to ascending, widely spreading and lianoid. Leaves reduced to mucronate sheaths, 3.5–10.2 mm long, closely appressed to culm, spaced 15-48 mm distant, initially light green to light brown maturing dark brown to brown-black, margin entire; cilia protruding through the mouth of the sheath as white tufts of woolly white hairs; hairs arising from the outer scale of the axillary bud enclosed within sheath; mucro persistent, 1.5-4.2 mm long, initially light green maturing dark brown, fine, sharp-pointed, strongly reflexed. Spikelets distant within uppermost sheaths. Male spikelets 1-2, 3.9-8.0 mm long, 1-6-flowered, 1 sessile and 1 stalked, each borne within a hard, mucronate sheath; tepals 6, narrow-linear, acute; stamens 3, filaments slender, > tepals, anthers 1.2-2.0 mm long, exserted beyond the floral bract. Female spikelets 3.5–7.0 mm long, solitary within 1-3 uppermost, bearded, obtuse sheaths, 1-flowered, subtended by 2 imbricate, empty floral bracts; tepals 6-4, very small, hyaline; styles 3, free. Fruit a hard, oval nut, 2.6 mm long, protruding over persistent tepals, sessile on a thick receptacle.
Differs from Empodisma robustum by the diminutive stature and slender growth habit; culms mostly < 1 mm in diameter, sheaths mostly < 7.5 mm long and spikelets generally < 6.0 mm long. Readily distinguished from the two other New Zealand restiad genera Sporadanthus and Apodasmia by the mostly widely spreading, decumbent, trailing to lianoid growth habit, and 1-6-flowered male and 1-flowered female spikelets.
August - December
November - March
Nuts are wind dispersed (Thorsen et al., 2009).
Easily grown from seed. Prefers an open, permanently damp, acidic soil but can be grown in dry soils as well. Not often cultivated.
minus: Small; from the Latin minor
Where To Buy
Not commercially available
The description in Flora II (Moore & Edgar 1970) includes two elements which are now treated as two species Empodisma minus and E. robustum.
Fact sheet prepared for NZPCN by P.J. de Lange (18 June 2005). Description based on fresh material and herbarium specimens.
References and further reading
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.
NZPCN Fact Sheet citation
Please cite as: de Lange, P.J. (Year at time of access): Empodisma minus Fact Sheet (content continuously updated). New Zealand Plant Conservation Network. https://www.nzpcn.org.nz/flora/species/empodisma-minus/ (Date website was queried)