Genoplesium firthii

Genoplesium firthii, commonly known as Firth's midge orchid and as Corunastylis firthii in Australia, is a small terrestrial orchid endemic to Tasmania. It has a single thin leaf fused to the flowering stem and up to six small, yellowish green or reddish flowers with a red labellum. It grows in coastal heath and scrub and is currently known only from a single population of about twelve plants near Coles Bay.

Firth's midge orchid
Scientific classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Monocots
Order: Asparagales
Family: Orchidaceae
Subfamily: Orchidoideae
Tribe: Diurideae
Genus: Genoplesium
Species:
G. firthii
Binomial name
Genoplesium firthii
Synonyms[2]

Description

Genoplesium firthii is a terrestrial, perennial, deciduous, herb with an underground tuber and a single thin leaf 50–80 mm (2–3 in) long and fused to the flowering stem with the free part 5–10 mm (0.2–0.4 in) long. Up to six yellowish green or reddish flowers are arranged along a flowering stem 10–15 mm (0.4–0.6 in) tall and much taller than the leaf. The flowers lean downwards and are about 4.5 mm (0.2 in) long and 3 mm (0.1 in) wide. As with others in the genus, the flowers are inverted so that the labellum is above the column rather than below it. The dorsal sepal is about 3 mm (0.1 in) long and 2.5 mm (0.1 in) wide with a small gland on the tip. The lateral sepals turn downwards, are about 4 mm (0.2 in) long, 1 mm (0.04 in) wide and spread apart from each other. They also have a small gland on the tip. The petals are about 2 mm (0.08 in) long and 1 mm (0.04 in) wide with a pointed tip and hairless edges. The labellum is red, egg-shaped with the narrower end towards the base, about 2.5 mm (0.1 in) long, 1.5 mm (0.06 in) wide, with irregular edges and a pointed tip. There is a callus in the centre of the labellum and extending nearly to its tip. Flowering occurs from January to March.[3][4][5]

Taxonomy and naming

Firth's midge orchid was first formally described in 1971 by Leonard Cady who gave it the name Prasophyllum firthii from a specimen collected near Bicheno. The description was published in The Orchadian.[6] In 1989, David Jones changed the name to Genoplesium firthii[7] and in 2005 changed the name again to Corunastylis firthii.[1]

Distribution and habitat

Genoplesium firthii grows on a roadside near Coles Bay.[4]

Conservation

Firth's midge orchid is only known from a single population containing about twelve plants. It was formerly also known to occur at Friendly Beaches Reserve but has not been seen there since 1973. The species is classified as Endangered under the Tasmanian Threatened Species Protection Act 1995 and as Critically Endangered under the Commonwealth Government Environment Protection and Biodiversity Conservation Act 1999 (EPBC) Act. The main threats to the species are road maintenance, trampling by people and cars, by weed invasion and inappropriate fire regimes.[4][5]

References
  1. "Corunastylis firthii". APNI. Retrieved 3 February 2018.
  2. "Genoplesium firthii". World Checklist of Selected Plant Families (WCSP). Royal Botanic Gardens, Kew.
  3. Jones, David L. (2006). A complete guide to native orchids of Australia including the island territories. Frenchs Forest, N.S.W.: New Holland. pp. 185–186. ISBN 1877069124.
  4. "Conservation Advice Genoplesium firthii" (PDF). Australian Government Department of the Environment. Retrieved 3 February 2018.
  5. "Threatened species listing statement - Firth's midge orchid - Corunastylis firthii". Tasmanian Government Department of Primary Industries, Water and Environment. Retrieved 3 February 2018.
  6. "Prasophyllum firthii". APNI. Retrieved 3 February 2018.
  7. "Genoplesium firthii". APNI. Retrieved 3 February 2018.
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