Corybas dienemus

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Windswept helmet-orchid
Scientific classification Red Pencil Icon.png
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Monocots
Order: Asparagales
Family: Orchidaceae
Subfamily: Orchidoideae
Tribe: Diurideae
Genus: Corybas
Species:
C. dienemus
Binomial name
Corybas dienemus
Synonyms [1]

Corybas dienemus, commonly known as the windswept helmet-orchid, is one of two helmet orchids endemic to Australia's subantarctic Macquarie Island, and the first orchid to be found there. It is a relatively small orchid with green flowers with purplish-red markings and was discovered in 1978.

Contents

Description

The windswept helmet-orchid is a relatively small (30–50 mm tall), terrestrial, tuberous, herbaceous plant that forms clonal colonies. The leaves are flattish, fleshy and solitary, dark green above and silvery-green underneath. The flower is erect, nestling in the leaf base, green with purplish-red markings, 25–30 mm long and 20–25 mm wide. It can be distinguished from its congener and the only other orchid on the island, the grooved helmet-orchid Corybas sulcatus , by its predominantly green flowers, compared with the predominantly dark red ones of C. sulcatus. [2] [3] [4]

Taxonomy and naming

This orchid was first discovered on Macquarie Island in 1978 and identified as Corybas macranthus, [5] which is widespread in New Zealand. [6] It was then recognised in 1993 by David Jones as a new species that he named Corybas dienemus. [7] In 2002, it was transferred to the reinstated genus Nematoceras as Nematoceras dienemum but that name has not been accepted by World Checklist of Selected Plant Families at Royal Botanic Gardens, Kew. [8] [9] The specific epithet (dienemum) is an Ancient Greek word meaning "windswept". [10]

Distribution and habitat

The orchid is known from ten sites on the northern half of Macquarie Island, where it inhabits the lower coastal terraces, not more than 30 m above sea level, where the vegetation is dominated by mosses that float on a substrate of waterlogged peat with a water table very close to the soil surface. The total known population comprises about 7500 plants. [2] [3]

Reproduction

The flowering period of the orchid is from November to January. It produces seeds annually but also reproduces vegetatively through the production of daughter root-tubers on lateral underground stolons. Its leaves die off in autumn, with new leaves emerging in spring. Although the life expectancy and age of sexual maturity of the orchid are unknown, it is likely that some clonal colonies have existed for several decades. The pollination method is unknown, though one possible pollinator is the Black Fungus Gnat (Bradysia watsoni), which is common on the coastal terraces where the orchid is found. [3]

Conservation

Macquarie Island is a nature reserve, a World Heritage Site and a UNESCO Biosphere Reserve. However, the windswept helmet-orchid is listed as endangered on the Tasmanian Threatened Species Protection Act 1995 because of its restricted distribution, small population and projected decline through ongoing habitat degradation caused by the grazing, digging and burrowing activities of rabbits. [11] Additional threats are the formation of seal wallows and, potentially, climate change. It is also listed as Critically Endangered under Australia's Environment Protection and Biodiversity Conservation Act 1999. [3]

In 2010, a plan to eliminate rabbits from Macquarie Island was implemented and aerial baiting was commenced. Later, hunters and dog handlers destroyed a few surviving rabbits and by 2014, rabbits had been eliminated from the island. [12] [13]

Related Research Articles

Macquarie Island Sub-Antarctic island of Australia

Macquarie Island, a UNESCO World Heritage Site, lies in the Southwestern Pacific Ocean, about halfway between New Zealand and Antarctica. Regionally part of Oceania and politically a part of Tasmania, Australia, since 1900, it became a Tasmanian State Reserve in 1978 and was inscribed on the World Heritage List in 1997.

<i>Corybas</i> (plant) Genus of orchids

Corybas, commonly known as helmet orchids, is a genus of about 120 species of plants in the orchid family, Orchidaceae. Helmet orchids are small, perennial, deciduous herbs and are nearly always terrestrial. They have a single leaf at their base and a single flower on a short stalk, the flower dominated by its large dorsal sepal and labellum. Species of Corybas are found in Australia, New Zealand, New Guinea, Southeast Asia, the Himalayas, southern China, many Pacific islands and a few sub-Antarctic islands.

Nematoceras is a genus of orchids, sometimes known as spider orchids, helmet orchids or spidery helmet-orchids, found mainly in New Zealand and its subantarctic islands, with two species on Australia's Macquarie Island. The genus was originally described in 1853 by Joseph Dalton Hooker who published his description in The botany of the Antarctic voyage of H.M. discovery ships Erebus and Terror. II. Flora Novae-Zelandiae. In 2002 David Jones, Mark Clements and Brian Molloy transferred some species of Corybas to Nematoceras but the move has not been accepted by the World Checklist of Selected Plant Families at Royal Botanic Gardens, Kew.

Corybas sulcatus, also known as the grooved helmet-orchid, is one of two helmet orchids endemic to Australia’s subantarctic Macquarie Island, and the second to be discovered. The specific epithet comes from the Latin sulcatus – “grooved”, with reference to the prominent groove in the labellum boss. It is a small, terrestrial, tuberous, herbaceous plant that forms clonal colonies. The flower is erect, mostly dark red, 25–30 mm long and 10–14 mm wide. The flowering period is November–December. It occurs on the plateau uplands of the island, growing in wet grassy seepage areas. It can be distinguished from the only other orchid on the island, Corybas dienemus, by its dark red flowers.

Macquarie Island orchid may refer to:

<i>Corybas aconitiflorus</i> Species of orchid

Corybas aconitiflorus, commonly known as the cradle orchid or spurred helmet orchid, is a species of terrestrial orchid endemic to eastern Australia, occurring from south-east Queensland to Tasmania. The small flowers have a hooded appearance as the uppermost sepal hides most of the rest of the flower. It is the type species of the genus Corybas.

Genoplesium littorale, commonly known as the Tuncurry midge orchid, and as Corunastylis littoralis in Australia, is a small terrestrial orchid endemic to New South Wales. It has a single thin leaf fused to the flowering stem and up to thirty small green flowers with a purple-brown labellum. It is only known from fewer than two thousand plants in a small area on the New South Wales North Coast and is critically endangered.

<i>Arthrochilus huntianus</i> Species of flowering plant

Arthrochilus huntianus, commonly known as common elbow orchid, is a flowering plant in the orchid family (Orchidaceae) and is endemic to south-eastern Australia. It has no leaves but an insect-like flower which has its labellum dangling like a lure away from the rest of the flower. Because of its thin, wiry stem and small, dull-coloured flowers, this orchid is difficult to locate. Like others in the genus, the flowers are pollinated by a species of thynnid wasp. Some authorities use the name Thynninorchis huntiana for this orchid.

Corybas abditus, commonly known as the swamp helmet orchid or small helmet orchid , is a species of terrestrial orchid endemic to Western Australia. It is a rare orchid with a single bluish green, heart-shaped leaf and a small flower with an enlarged dorsal sepal and tube-shaped labellum.

<i>Corybas acuminatus</i> Species of orchid

Corybas acuminatus, commonly known as the dancing spider orchid or helmet flower, is a species of terrestrial orchid endemic to New Zealand. It has a triangular, sharply pointed leaf and a small translucent, greenish-white flower with purple markings and with very long sepals. It is found on both the main islands of New Zealand and also some of the off-shore islands.

Corybas abellianus, commonly known as the nodding helmet orchid, is a species of terrestrial orchid endemic to tropical north Queensland. It forms small colonies and has single heart-shaped, dark green leaf with a silvery white lower side and a reddish purple flower with a curved dorsal sepal.

Corybas cerasinus, commonly known as the red helmet orchid, is a species of terrestrial orchid endemic to tropical north Queensland. It has a single bluish green, heart-shaped leaf and a cherry red to dark maroon flower with its curved dorsal sepal obscuring its labellum which has an upturned tip.

<i>Corybas confusus</i> Species of orchid

Corybas confusus, commonly known as the spider orchid is a species of terrestrial orchid endemic to New Zealand. It has a single heart-shaped leaf and a single dark green or light green flower with reddish maroon streaks and blotches and long, thread-like lateral sepals and petals. It grows in highland areas on both main islands.

Corybas dentatus, commonly known as the Lofty Ranges helmet orchid, is a species of terrestrial orchid endemic to South Australia. It has a more or less round leaf and a single purplish and green flower. It is only known from two locations and is listed as "vulnerable" under the Environment Protection and Biodiversity Conservation Act.

Corybas expansus, commonly known as the flared helmet orchid, is a species of terrestrial orchid endemic to South Australia. It has a heart-shaped to more or less round leaf and a single purplish flower with greenish or transparent areas. It is a vulnerable species, found in near-coastal sand and leaf litter.

<i>Corybas fimbriatus</i> Species of orchid

Corybas fimbriatus, commonly known as the fringed helmet orchid, is a species of terrestrial orchid endemic to eastern Australia. It has a broad egg-shaped to round leaf and a dark reddish purple to crimson flower with translucent patches. It is similar to C. hispidus but its labellum lacks a creamy-white centre and is not covered with bristly hairs.

Corybas fordhamii, commonly known as the banded helmet orchid or swamp helmet orchid, is a species of terrestrial orchid endemic to south-eastern Australia. It has an egg-shaped to heart-shaped leaf and a reddish to reddish purple flower which leans forward. It is similar to C. unguiculatis which does not grow in swamps and has a different labellum.

Corybas montanus, commonly known as the montane helmet orchid, is a species of terrestrial orchid endemic to Queensland. It forms small colonies and has single heart-shaped to round leaf and a reddish, self-pollinating flower with a curved dorsal sepal. It is only known from the Mount Barney National Park in south-east Queensland.

<i>Corybas recurvus</i> Species of orchid

Corybas recurvus, commonly known as the western helmet orchid or common helmet is a species of terrestrial orchid endemic to Western Australia. It has round or heart-shaped leaf and a dark reddish purple or purplish black flower. It is widespread and common between Bunbury and Albany.

<i>Corybas undulatus</i> Species of orchid

Corybas undulatus, commonly known as tailed helmet orchid, is a species of terrestrial orchid endemic to eastern Australia. It has a single leaf and a single translucent grey flower with reddish markings, and a labellum with a bristly surface, fine teeth on the edge and a small tail on the tip.

References

  1. 1 2 "Corybas dienemus". World Checklist of Selected Plant Families (WCSP). Royal Botanic Gardens, Kew.
  2. 1 2 Clements, Mark A.; Jones, David L. (2007). "A new species of Nematoceras and characterisation of N. dienemum (Orchidaceae), both from subantarctic Macquarie Island". Telopea. 11 (4): 405–411. doi: 10.7751/telopea20075739 .
  3. 1 2 3 4 "Approved Conservation Advice for Nematoceras dienemum (Windswept Helmet-orchid)" (PDF). Australian Government Department of the Environment. Retrieved 27 April 2017.
  4. ↑ Jones, David L. (2006). A complete guide to native orchids of Australia including the island territories. Frenchs Forest, N.S.W.: New Holland. p. 173. ISBN   1877069124.
  5. ↑ "Corybas macranthus". APNI. Retrieved 27 April 2017.
  6. ↑ "Corybas macranthus". New Zealand Native Orchids. Retrieved 27 April 2017.
  7. ↑ "Corybas dienemus". APNI. Retrieved 27 April 2017.
  8. ↑ "Nematoceras dienemum". APNI. Retrieved 27 April 2017.
  9. ↑ St George, Ian. "Nematoceras dienemum". New Zealand Native Orchids. Retrieved 27 April 2017.
  10. ↑ Brown, Roland Wilbur (1956). The Composition of Scientific Words. Washington, D.C.: Smithsonian Institution Press. p. 857.
  11. ↑ "Nematoceras dienemum - Tasmanian threatened species listing statement" (PDF). Government of Tasmania Department of Primary Industries, Parks, Water and Environment. Retrieved 27 July 2020.
  12. ↑ "Macquarie Island Pest Eradication Project". Tasmanian Government Parks and Wildlife Service. Retrieved 27 April 2017.
  13. ↑ Breen, Fiona (20 April 2015). "Macquarie Island wildlife recovering after rabbit eradication". Australian Broadcasting Corporation. Landline. Retrieved 27 April 2017.
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