Empodisma robustum
Common name
wire rush
Synonyms
None first described in 2012.
Family
Restionaceae
Flora category
Vascular – Native
Endemic taxon
No
Endemic genus
No
Endemic family
No
Structural class
Rushes & Allied Plants
NVS code
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.
EMPROB
Chromosome number
2n = 24
Current conservation status
The conservation 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.
Please note, threat classifications are often suggested by authors when publications fall between NZTCS assessment periods – an interim threat classification status has not been assessed by the NZTCS panel.
- Conservation status of New Zealand indigenous vascular plants, 2017 . 2018. 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. Department of Conservation. Source: NZTCS and licensed by DOC for reuse under the Creative Commons Attribution 4.0 International licence.
2017 | At Risk – Declining
Previous conservation statuses
2012 | Not Threatened
2009 | Not Threatened
Distribution
Endemic. New Zealand: North Island (Te Aupouri Peninsula south to the lower Waikato).
Habitat
Empodisma robustum is restricted to ombrotrophic raised peat bogs where it often coexists with Sporadanthus ferrugineus, fens and gumland heathland peats. It is often locally abundant.
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). If you have suggestions for the Wetland Indicator Status Rating, please contact: [Enable JavaScript to view protected content]
OBL: Obligate Wetland
Almost always is a hydrophyte, rarely in uplands (non-wetlands).
Detailed description
Dioecious, perennial herb producing numerous, branched, flexuose culms collectively forming densely interwoven tangles. Rhizome rather robust for plant, erect, up to 12 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, 1.2–1.8 mm diameter, densely covered in pinkish-white root hairs. Culms 0.38–2.2 m, 0.9–2.2 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, 5.2–21.0 mm long, closely appressed to culm, spaced 20–70 mm apart, initially light green to light brown maturing dark brown, 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, 2.2–7.5 mm long, initially light green maturing dark brown, fine, sharp-pointed (accicular), strongly reflexed from leaf sheath. Spikelets brown, distant within uppermost sheaths. Male spikelets 1–2, 6.8–9.0 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 1.9–2.5 m, exserted beyond the floral bract. Female spikelets 5.8–8.9 mm, solitary within 1–3 uppermost, bearded, obtuse sheaths, 1-flowered, subtended by 2 imbricate, empty floral bracts; tepals 4–6, very small, hyaline; styles 3, free. Fruit a hard nut, 2.7 mm long, dark brown, ovoid, protruding over persistent tepals, sessile on a thick receptacle.
Similar taxa
Empodisma minus differs from E. robustum by its 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 tall 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.
Flowering
August–October
Flower colours
Yellow
Fruiting
November–March
Propagation technique
Easily grown from fresh seed and by the division of established plants. Despite its natural restriction to acidic wetlands. Empodisma robustum can be easily grown in a range of media though it does best in full sun in a permanently damp soil.
Etymology
empodisma: Tangle-foot
robustum: Sturdy
Where To Buy
Not commercially available
Taxonomic Notes
The description (as Calorophus minor) in Flora II (Moore & Edgar 1970) includes two elements which are now treated as two species Empodisma minus and E. robustum.
Attribution
Fact sheet prepared for NZPCN by P.J. de Lange 26 June 2012. Description from Wagstaff & Clarkson (2012).
References and further reading
Moore LB, Edgar E. 1970. Flora of New Zealand, Volume II. Indigenous Tracheophyta: Monocotyledones except Gramineae. Government Printer, Wellington, NZ. 354 p.
Wagstaff SJ, Clarkson BR. 2012. Systematics and ecology of the Australasian genus Empodisma (Restionaceae) and description of a new species from peatlands in northern New Zealand. Phytokeys 13: 39-79. https://doi.org/10.3897/phytokeys.13.3259.
NZPCN Fact Sheet citation
Please cite as: de Lange, P.J. (Year at time of access): Empodisma robustum Fact Sheet (content continuously updated). New Zealand Plant Conservation Network. https://www.nzpcn.org.nz/flora/species/empodisma-robustum/ (Date website was queried)