Empodisma minus

  • Mt Ruapehu, January

Species

Empodisma minus

Etymology

Empodisma: Tangle-foot
minus: small; from the Latin minor

Common Name(s)

wire rush, lesser wire rush

Current Threat Status

2012 - Not Threatened

Previous Threat Status

2009 - Not Threatened
2004 - Not Threatened

Authority

Empodisma minus (Hook.f.) L.A.S.Johnson et D.F.Cutler

Family

Restionaceae

Flora Category

Vascular - Native

Synonyms

Calorophus minor Hook.f.; Calorophus elongatus var. minor Hook.f.; Hypolaena lateriflora var. minor (Hook.f.) Cheeseman

Distribution

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.

Habitat

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). Tolerating extremely acidic conditions (up to pH 2.5).

Features

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.

Similar Taxa

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.

Flowering

August - December

Main Flower Colour

Yellow

Other Flower Colour

Black

Fruiting

November - March

Propagation Technique

Easily grown from seed. Prefers an open, permanently damp, acidic soil but can be grown in dry soils as well. Not often cultivated.

Threats

Not Threatened

Chromosome No.

2n = 24

Endemic Taxon

No

Endemic Genus

No

Endemic Family

No

Where To Buy

Not commercially available

Taxonomic Notes

The description in Flora II (Moore & Edgar 1970) includes two elements which are now treated as two species Empodisma minus and E. robustum.

 

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

This page last updated on 14 Sep 2014

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