Corybas iridescens


Corybas: helmet flower
iridescens: Becoming iridescent (from the Latin iridis, meaning the rainbow)

Common Name(s)

Spider Orchid, Big Red

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


Corybas iridescens Irwin et Molloy,



Flora Category

Vascular - Native

Structural Class



Corysanthes iridescens (Irwin et Molloy) Szlach.; Nematoceras iridescens (Irwin & Molloy) Molloy, D.L.Jones et M.A.Clem.


Endemic. North, South and Chatham Islands.


Coastal to montane (up to 1100 m a.s.l.). Favouring base rich substrates, especially calcaerous mudstones, siltstones (both known as Papa rock), and limestone but also on basalt. Usually in, or near seepages or on the margins of slow-flowing streams


Terrestrial, tuberous, glabrous, summer-green herb forming extensive colonies. Tuberoids globose to ellipsoid on extended roots. Leaf solitary, fleshy, more or less subcoriaceous, usually spreading and held flat to the ground surface; shortly petiolate, petiole 3.0-10.0 x 1.5-3.0 mm; lamina 20-40x 15-35 mm, or larger, ovate-oblong or bluntly wedge-shaped, often pandurate, squared and apiculate at apex, with apiculus decurved, rounded and cordate at base; midrib grooved above, ridged beneath; leaf colour dull dark green above with purple flecks on margins, on midrib, or overall, silvery beneath. Flowers 1(-2), 12-20 mm long, dark red-green, dominated by labellum, dorsal sepal and long filiform petals and lateral sepals; peduncle 4-5 mm long. Ovary 4-8 mm long, green or cream, purple-flecked, curved, subtended by two unequal floral bracts, the smaller 3-5 mm long, linear-subulate, terete the larger equal to or exceeding the ovary, 7-10 mm long, lanceolate, green flecked with purple. Dorsal sepal extending well past labellum 20-35 x 8-12 mm, narrowly ovate in outline when flattened, concave, cucullate and arching over the labellum tube, with apex usually recurved; green spotted and/or striped with purple. Lateral sepals 50.0-70.0 x 0.5-1.0 mm at widest point; filiform, greatly exceeding labellum; translucent white with purple striations, horizontal to suberect and projecting forwards and outwards; suberect to erect and spreading; channelled, and twisted. Petals 40.0-60.0 x 0.5-1.0 mm at widest point, slightly shorter than lateral sepals, filiform, greatly exceeding labellum, translucent white with purple striations, horizontal to suberect, projecting forwards and outwards; channelled, auriculate on the base of the column. Auricles short, projecting downwards and forwards, with apertures 1.5-2.5 mm across. Labellum conspicuous, dark red, maroon-red to almost black, sometimes striped with green at front, iridescent when wet; labellum tube 5-7 mm long, erect at first then abruptly deflexed through 160-180 degrees, and expanding into the lamina with a prominent bead-like callus in throat of tube at bend; lamina 10-20 x 10-15 mm, broadly ovate to orbicular; upper margins folded inwards, mostly overlapping; lower surface spreading, deflexed against ovary; with margins erose-papillose, and a long median apiculus; inner surface with dense, minute, retrorse papillae and ridged veins; throat of labellum tube high on lamina. Column 3-4 mm long, broadest and ridged at base, inclined backwards, minutely winged. Stigma scutiform to oblong, 1 mm diameter, concave. Anther 1 mm, purple-obtuse. Pollinia 4, united in pairs, 1.0 x 0.7 mm, oblong, mealy, yellow. Capsule 12-20 x 5-7 mm, elliptic, initially pale green later brown, on greatly elongated peduncle.

Similar Taxa

Distinguished by the combination of shortly petiolate, broadly wedge-shaped, usually spotted leaves; broad dorsal sepal; subequal petals and lateral sepals; abruptly deflexed, dark red, almost black labellum, which is strongly iridescent when wet; and by the prominent bead-like callus at the entrance to the labellum tube.


August - November

Flower Colours

Green,Red / Pink


October - January

Propagation Technique

Difficult - should not be removed from the wild.


Not Threatened

Chromosome No.

2n = 36

Endemic Taxon


Endemic Genus


Endemic Family


Where To Buy

Not commercially available


Considerable research is underway to investigate the validity of the segregate genera split from Corybas R.Br. by Jones et al. (2002). Whilst much of that work has yet to be published, on advice from Australian Orchidologists Peter Weston and Stephen Hopper (pers. comm., July 2011, November 2014), all of the segregate genera recognised for New Zealand by Jones et al. (2002) are returned to Corybas

Recently Lehnebach (2016) has made three combinations for those Nematoceras lacking valid names in Corybas. This action now enables the full transfer of Nematoceras back to Corybas. However, as of writing, a formal publication rejecting the segregation of Corybas by Jones et al. (2002) has yet to be published. Lehnebach cites an unpublished PhD (Lyon 2014) that indicates this move is imminent.


Description based on Molloy and Irwin (1996).

References and further reading

Jones, D.L.; Clements, M.A.; Sharma, I.K.; Mackenzie, A.M.; Molloy, B.P.J. 2002: Nomenclatural notes arising from studies into the Tribe Diurideae (Orchidaceae). The Orchadian 13: 437-468.

Lehnebach, C. 2016: New combinations and a replacement name for three New Zealand spider orchids (Corybas). The New Zealand Native Orchid Journal 139. 4-5.

Lyon, S. P. 2014: Molecular systematics, biogeography, and mycorrhizal associations in the Acianthinae (Orchidaceae), with a focus on the genus Corybas. PhD Thesis, University of Wisconsin-Madison. USA.

Molloy, B.P.J.; Irwin, J.B. 1996: Two new species of Corybas (Orchidaceae) from New Zealand, and taxonomic notes on C. rivularis and C. orbiculatus. New Zealand Journal of Botany 34: 1-10.

This page last updated on 16 Jan 2016