Genoplesium

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Genoplesium
Fringed Orchid Long Track.JPG
G. fimbriatum in Ku-ring-gai Chase National Park
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Monocots
Order: Asparagales
Family: Orchidaceae
Subfamily: Orchidoideae
Tribe: Diurideae
Subtribe: Prasophyllinae
Genus: Genoplesium
R.Br. [1]
Synonyms [1]

Genoplesium commonly known as midge orchids, is a genus of about 50 species of flowering plants in the orchid family, Orchidaceae and is found in Australia, New Zealand and New Caledonia. Midge orchids are terrestrial herbs with a single leaf at the base of the plant. They are similar to orchids in the genus Prasophyllum in that plants without flowers have a hollow, onion-like leaf. The flowers are small but often scented and attractive to their insect pollinators. There is disagreement about which species belong to this genus and some taxonomists suggest that most belong in the genus Corunastylis .

Contents

Description

Orchids in the genus Genoplesium are terrestrial, perennial, deciduous, sympodial herbs, usually with a few inconspicuous, fine roots and a pair of more or less spherical tubers. The tubers are partly covered by a protective fibrous sheath which extends to the soil surface. Replacement tubers form at the end of short root-like stolons. Orchids in this genus do not reproduce using "daughter" tubers, but rely on their flowers for reproduction. A single long, cylindrical, glabrous leaf develops near the base of the plant and is fused to the flowering stem. The leaf of flowering plants is solid but those of sterile plants are hollow. [2] [3] [4]

The inflorescence is a spike or raceme with a few to many non-resupinate flowers which are often have reddish brown or purple parts and often smell fruity. The dorsal sepal is usually shorter and wider than two lateral sepals, dished on the lower surface and often forms a hood over the column. The lateral sepals are often joined near their bases and the lateral petals are shorter and narrower than the sepals. As is usual in orchids, one petal is highly modified as the central labellum, much different from the other petals and sepals. The labellum is above the column and joined to it by a flexible attachment, so that the labellum vibrates in a breeze. The edge of the labellum sometimes has fine teeth, glands or hairs. The labellum has a callus which consists often covers its surface and which consists of a raised, fleshy plate. The sexual parts of the flower are fused to the column which is short and has narrow wings, often with an extension at the front. Midge orchids usually flower in summer, autumn or winter, depending on species, and the fruit that follows flowering is a non-fleshy, dehiscent capsule containing up to 500 seeds. [2] [3] [4]

Taxonomy and naming

The genus Genoplesium was first formally described by Robert Brown in 1810 and the description was published in Prodromus Florae Novae Hollandiae . The type species is G. baueri . [5] [6]

The name Genoplesium is derived from the Ancient Greek words genos meaning "race", "stock" or "kind" [7] :366 and plesios meaning "near" [7] :618 referring to the similarity of these orchids to those in the genus Prasophyllum . [3]

David Jones and Mark Clements proposed moving all but one species of Genoplesium to Corunastylis . The change has been accepted by the Royal Botanic Gardens Victoria who list twelve species of Corunastylis but not Plants of the World Online. [1] [8]

Distribution and habitat

Midge orchids mainly occur in Queensland, New South Wales, Victoria, Tasmania and South Australia. [3] There is one species ( G. calopterum ) in New Caledonia and two ( G. nudum and G. pumilum ) in New Zealand. [9] Most Genoplesium species occur in near-coastal regions but also grow in montane and sub-alpine areas. In Australia they are most common in moss beds over rock, in forest, woodland, heath and mallee. Genoplesium species in New Zealand grow in grassy places as well as in swamps and the New Caledonian species grows in stunted maquis. [3]

Ecology

Some of the characteristics of the flowers of midge orchids, such as small size, dull colours and hairy parts waving in a breeze, suggest pollination by small flies. Some studies have suggested that the flowers are pollinated exclusively by flies of the Superfamily Chloropoidea (now in the Family Milichiidae ). A few species, such as the New Zealand G. nudum appear to exclusively self-pollinate. [3]

Species list

The species recognised by the Plants of the World Online as of July 2023 are: [10]

See also

Related Research Articles

<i>Pterostylis</i> Genus of plants

Pterostylis is a genus of about 300 species of plants in the orchid family, Orchidaceae. Commonly called greenhood orchids, they are terrestrial, deciduous, perennial, tuberous, herbs found in Australia, New Zealand, New Guinea, New Caledonia and one Indonesian island. The flowers are mostly green, sometimes with brown, reddish or white stripes, and are distinguished from other orchids by their unusual flower structures and pollination mechanism.

<i>Diuris</i> Genus of plants

Diuris, commonly known as donkey orchids, bee orchids, nanny goat orchids or pansy orchids, is a genus of more than sixty species of flowering plants in the orchid family, Orchidaceae and is endemic to Australia, apart from one species endemic to Timor. The name "Diuris" refers to the hanging sepals but the common name "donkey orchid", derives from the ear-like petals common to all species. Many have mainly yellow flowers with darker markings and are thought to mimic nectar-producing flowers which open at the same time.

<i>Chiloglottis</i> Genus of orchids

Chiloglottis, commonly known as wasp orchids, ant orchids or bird orchids, is a genus of about 25 species of flowering plants in the orchid family, Orchidaceae and is found in eastern Australia and New Zealand. Wasp orchids are terrestrial herbs which grow in colonies of genetically identical plants. They usually have two leaves at the base of the plant and a single resupinate ("upside-down") flower. The labellum is more or less diamond-shaped and has calli resembling the body of a wingless female wasp.

<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.

<i>Genoplesium plumosum</i> Species of orchid

Genoplesium plumosum, commonly known as the Tallong midge-orchid or plumed midge-orchid, is a species of orchid endemic to New South Wales. It is a small orchid only known from a few sites near the towns of Tallong and Wingello on the Southern Tablelands and is only relatively easy to find for about a month, when it flowers. It has been classified as "Endangered" under the EPBC Act.

Corunastylis is a historically recognized genus of about 50 species of orchids, native to Australia and New Zealand, now included in the genera Genoplesium and Prasophyllum.

<i>Genoplesium nigricans</i> Species of orchid

Genoplesium nigricans, commonly known as mallee midge orchid, is a species of orchid endemic to Australia. It is a terrestrial herb with a single leaf mostly surrounding the stem, and up to 50 tiny, greenish flowers with a deep maroon-coloured labellum and often have a fruity fragrance. Australian authorities use the name Corunastylis tepperi, a widespread species which has been confused with Corunastylis nigricans, a species with purplish brown flowers and which only occurs on Kangaroo Island and the Eyre Peninsula.

<i>Genoplesium nudum</i> Species of orchid

Genoplesium nudum, commonly known as the tiny midge orchid in Australia or the red midge orchid in New Zealand, is a small terrestrial orchid native to south-eastern Australia and New Zealand. It has a single thin leaf fused to the flowering stem and up to forty small, reddish-purple or green and red flowers. Australian and New Zealand authorities use the name Corunastylis nuda but Genoplesium nudum and Prasophyllum transversum are used by the World Checklist of Selected Plant Families.

Genoplesium rufum, commonly known as the rufous midge-orchid, is a species of orchid endemic to New South Wales. It has a single thin, wiry leaf and up to twenty five drooping, pinkish or reddish flowers on a flowering stem which is fused to the lower part of the leaf. It was formerly thought to range from Queensland to South Australia and Tasmania but specimens in other states are now assigned to Genoplesium clivicola.

<i>Genoplesium nudiscapum</i> Species of orchid

Genoplesium nudiscapum, commonly known as the bare midge orchid, is a species of small terrestrial orchid endemic to Tasmania. It has a single thin leaf fused to the flowering stem and up to twenty small, green and reddish-brown flowers. It was thought to be extinct, since it had not been seen since 1852 but was rediscovered in 2008. The species has also been described as occurring on continental Australia. The species is known as Corunastylis nudiscapa in Tasmania.

<i>Genoplesium morrisii</i> Species of orchid

Genoplesium morrisii, commonly known as the bearded midge orchid and known as Corunastylis morrisii in Australia, is a small terrestrial orchid endemic to south-eastern Australia. It has a single thin leaf fused to the flowering stem and up to fifteen small, dark purplish-black or green and purple flowers.

Genoplesium brachystachyum, commonly known as the Rocky Cape midge orchid or short-spike midge orchid, is a species of small terrestrial orchid endemic to Tasmania. It has a single thin leaf fused to the flowering stem and up to twelve small, green to brownish green, and reddish flowers. It usually grows in heath in rocky places near the coast.

Genoplesium eriochilum, commonly known as the Mount Wilson midge orchid, is a species of small terrestrial orchid endemic to the Blue Mountains. It has a single thin leaf fused to the flowering stem and up to twenty small, crowded, dark purplish brown flowers. It usually grows between low shrubs and sedges.

Genoplesium firthii, commonly known as Firth's midge orchid, is a species of 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 only known from a single population of about twelve plants near Coles Bay.

Genoplesium parvicallum, commonly known as the mountain-top midge-orchid, is a species of orchid which is endemic to Queensland. It is a small orchid with up to twenty five greenish flowers with purplish brown marking and is only known from mountaintops in the McPherson Range. It is treated as Corunastylis parvicalla in Queensland.

<i>Genoplesium ruppii</i> Species of orchid

Genoplesium ruppii, commonly known as Rupp's midge orchid, is a species of small terrestrial orchid that is endemic to eastern Australia. It has a single thin leaf fused to the flowering stem and up to twenty five small, hairy green flowers with a purple labellum.

Genoplesium sagittiferum, commonly known as the horned midge orchid, is a species of small terrestrial orchid that is endemic to New South Wales. It has a single thin leaf fused to the flowering stem and up to ten small, yellowish-green flowers with a hairy reddish labellum.

Genoplesium trifidum, commonly known as the trifid midge orchid, is a small terrestrial orchid endemic to New South Wales. It has a single thin leaf fused to the flowering stem and up to twenty five dark purplish-black and green flowers. It grows in heath in scattered places in the Sydney basin.

Genoplesium mucronatum is a species of small terrestrial orchid endemic to eastern New South Wales. It has a single leaf fused to the flowering stem and between six and twelve green and reddish-purple flowers.

References

  1. 1 2 3 "Genoplesium". Plants of the World Online. Retrieved 5 August 2023.
  2. 1 2 Jones, David L. (1998). "A Taxonomic Review of Prasophyllum R.Br. in Tasmania". Australian Orchid Research. 3: 86–93.
  3. 1 2 3 4 5 6 Pridgeon, Alec M.; Cribb, Phillip J.; Chase, Mark W.; Rasmussen, Finn, eds. (2001). Genera Orchidacearum, Volume 2, Orchidoideae (part 1). Oxford, England: Oxford University Press. pp. 177–181. ISBN   0198507100.
  4. 1 2 Jones, David L. "Genus Genoplesium". Royal Botanic Garden Sydney: plantnet. Retrieved 12 July 2016.
  5. "Prasophyllum". APNI. Retrieved 11 July 2016.
  6. Brown, Robert (1810). Prodromus Florae Novae Hollandiae. London. p. 319. Retrieved 12 July 2016.
  7. 1 2 Brown, Roland Wilbur (1956). The Composition of Scientific Words. Washington, D.C.: Smithsonian Institution Press.
  8. "Flora of Victoria: Corunastylis". Royal Botanic Gardens Victoria. Retrieved 12 July 2016.
  9. "Species List". New Zealand Native Orchids; New Zealand Orchid Group. Archived from the original on 22 July 2013. Retrieved 12 July 2016.
  10. "Genoplesium". Plants of the World Online. Retrieved 5 August 2023.