Corybas macranthus
Common names
silver-back spider orchid
Biostatus
Native – Endemic taxon
Category
Vascular
Structural class
Orchids
Flower colours
Red/Pink, Yellow
Detailed description
Terrestrial, tuberous, spring to summer green perennial forming dense colonies. Plant at flowering 40–100 mm tall. Leaf solitary, distinctly petiolate, petiole hyaline to white, more or less fleshy up to 60 mm long, suberect, ascending; lamina firmly fleshy, up to 40 × 40 mm, mostly green flecked or spotted with purple, or dark green above, silvery green to white beneath, orbicular to oblong-oval, apiculate, base rounded. Floral bract minute, < ovary, narrowly deltoid, initially closely sheathing spreading at flower anthesis. Dorsal sepal mostly shorter than labellum, hyaline yellow-green to greenish-white flecked with crimson or completely wine red, rather long and narrow-lanceolate, acute to shortly acuminate, arching over tubular portion of labellum; lateral sepals dark pink to crimson, filiform, greatly exceeding labellum. Petals similar to lateral sepals but usually much shorter. Labellum completely dark maroon-black or wine red, or dark maroon-black with a greenish throat, auriculate at base, lamina abruptly deflexed, funnelform, broadly expanded all round, margin minutely denticulate with a median apiculus, inner surface rough with short, sharp, retrorse papillae
Similar taxa
The stout, fleshy leaf which is usually held up above the flower, and widely flaring trumpet shaped dark maroon-black or wine red labellum, and very narrowly lanceolate dorsal sepal distinguish this species from all except the little known Corybas papillosus. Corybas papillosus differs from C. macranthus mainly by its bicoloured labellum (dark red to purple-red in the upper half, pale pink grading through to whitish in the lower half).
Distribution
Endemic. New Zealand: North Island, South Island, Stewart Island/Rakiura, Chatham Islands, Auckland Islands and Campbell Island/Motu Ihupuku.
Habitat
Lowland to subalpine (up to 1200 m a.s.l.) usually in damp, shaded to well-lit seepages, or in shaded sites under tall forest or associated with rock overhangs (then often in very dry sites). Favouring base-rich substrates such as calcareous mudstones, siltstones, limestones, dolomite or marble; also on basalt and basaltic-andesites, and soils derived from these.
Current conservation status
The conservation status of all known New Zealand vascular plant taxa at the rank of species and below were reassessed in 2022-2023 using the New Zealand Threat Classification System (NZTCS) – more information about this can be found on the NZTCS website. This report includes replaces all previous NZTCS lists for vascular plants. Previous assessments can be found here.
- Conservation status of vascular plants in Aotearoa New Zealand, 2023. 2024. Peter J. de Lange, Jane Gosden, Shannel P. Courtney, Alexander J. Fergus, John W. Barkla, Sarah M. Beadel, Paul D. Champion, Rowan Hindmarsh-Walls, Troy Makan and Pascale Michel Department of Conservation. Source: NZTCS and licensed by DOC for reuse under the Creative Commons Attribution 4.0 International licence.
2023 | Not Threatened
Detailed taxonomy
Genus
Family
Synonyms
Corysanthes macrantha (Hook.f.) Hook.f.; Nematoceras macranthum Hook.f.
Taxonomic notes
Segregate genera that were split from Corybas R.Br. by Jones et al. (2002) were not universally accepted and further research has been carried out into the genus. On advice from Australian Orchidologists Peter Weston and Stephen Hopper (pers. comm., July 2011, November 2014), NZPCN has returned all of the segregate genera recognised for New Zealand by Jones et al. (2002) to Corybas (see also Lyon 2014).
Lehnebach (2016) 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.
Endemic taxon
Yes
Endemic genus
No
Endemic family
No
Ecology
Flowering
September–January
Fruiting
October–February
Propagation technique
Difficult—should not be removed from the wild. Can be grown in basic orchid mix consists of 2 parts medium coarse sand, ideally clean river sand; 2 parts soil, humus or leaf-mould; 1 part weathered sawdust or rotting wood; 1 part granulated bark. Many Corybas thrive when more leaf-mould is added, and the plants grown in 50-70% shade, in the cooler, darker end of the shade-house, in pots kept moist throughout the growing period.
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]
FACW: Facultative Wetland
Usually is a hydrophyte but occasionally found in uplands (non-wetlands).
Other information
Etymology
corybas: Helmet flower
Manaaki Whenua Online Interactive Key
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.
CORMAC
Chromosome number
2n = 36
Previous conservation statuses
The conservation status of all known New Zealand vascular plant taxa at the rank of species and below were reassessed in 2022-2023 using the New Zealand Threat Classification System (NZTCS) – more information about this can be found on the NZTCS website. This report includes replaces all previous NZTCS lists for vascular plants. Previous assessments can be found here.
- Conservation status of vascular plants in Aotearoa New Zealand, 2023. 2024. Peter J. de Lange, Jane Gosden, Shannel P. Courtney, Alexander J. Fergus, John W. Barkla, Sarah M. Beadel, Paul D. Champion, Rowan Hindmarsh-Walls, Troy Makan and Pascale Michel Department of Conservation. Source: NZTCS and licensed by DOC for reuse under the Creative Commons Attribution 4.0 International licence.
2017 | Not Threatened
2012 | Not Threatened
2009 | Not Threatened
2004 | Not Threatened
Regional conservation statuses
Auckland: 2025 | Regionally Not Threatened | Qualifiers: DPS, DPT
The regional threat classification system leverages off the national assessments in the NZTCS, providing information relevant for the regional context. Auckland conservation status information is sourced from the “Conservation status of vascular plant species in Tāmaki Makaurau / Auckland” Simpkins E et al. (2025) report.
Otago: 2025 | Regionally Not Threatened
The regional threat classification system leverages off the national assessments in the NZTCS, providing information relevant for the regional context. Otago conservation status information is sourced from the “Conservation Status of Indigenous Vascular Plants in Otago, 2025” Jarvie S et al. (2025) report.
Referencing and citations
References and further reading
Jones DL, Clements MA, Sharma IK, Mackenzie AM, Molloy BPJ. 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 SP. 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. https://asset.library.wisc.edu/1711.dl/UAXO3VHO6P7EH8Y/R/file-19145.pdf.
Moore LB, Edgar E. 1970. Flora of New Zealand, Volume II. Indigenous Tracheophyta: Monocotyledones except Gramineae. Government Printer, Wellington, NZ. 354 p.
Attribution
Fact Sheet prepared for NZPCN by P.J. de Lange 14 April 2007. Description adapted from Moore and Edgar (1970).
Some of this factsheet information is derived from Flora of New Zealand Online and is used under a Creative Commons Attribution 3.0 New Zealand licence.