Acianthus

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Acianthus
Acianthus exsertus (24997834335).jpg
Acianthus exsertus
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: Acianthinae
Genus: Acianthus
R.Br. [1]
Synonyms [1]
List
    • Acianthella D.L.Jones & M.A.Clem.
    • AcianthopsisM.A.Clem. & D.L.Jones
    • Acianthopsis Szlach. nom. illeg.
    • AcianthusR.Br. sect. Acianthus
    • Acianthus sect. Macropetalus Kores
    • AcianthusR.Br. subg. Acianthus
    • Acianthus subg. UniviscidiatiKores
    • Acianthus subg. UniviscidiatusKores orth. var.
    • NemacianthusD.L.Jones & M.A.Clem.
    • UniviscidiatusSzlach. nom. inval.
    • UniviscidiatusD.L.Jones, M.A.Clem., I.K.Sharma, A.M.Mack. & Molloy nom. inval.
    • Univiscidiatus sect. MacropetalusSzlach. nom. inval.

Acianthus, commonly known as mosquito orchids, is a genus of about twelve species of plants in the orchid family, Orchidaceae. Mosquito orchids are terrestrial herbs with a single, heart-shaped, usually ground-hugging leaf and one to many small, green, pinkish or purplish flowers on a fleshy stalk. They are found in New Caledonia, Australia and New Zealand.

Contents

Description

Orchids in the genus Acianthus are terrestrial, perennial, deciduous, sympodial herbs with a single egg-shaped, heart-shaped or lobed leaf at the base. They have small, roughly spherical, underground tubers from which the flower stems arise. Lacking true roots, they have root-like stolons which develop "daughter" tubers at their ends. These orchids spend the dry, summer months dormant until, following late-summer or autumn rains, the leaf appears. The leaf is glabrous, sometimes ground-hugging, more usually held above the ground and is often purplish-red on the lower surface. Sometimes the leaves of plants with flowers are different from those lacking them. The leaves of all Australian species are very similar, making them hard to identify to species level in the absence of flowers. [2] [3] [4] [5] [6] [7] [8] [9]

Flowers appear in the cooler months, usually in autumn, winter or spring, There are one to many resupinate small, green, pinkish or purplish flowers 4 to 5 mm (0.16 to 0.20 in) in diameter. The flowers are held on an upright, narrow but fleshy stalk, blend in with their surrounding and often resemble mosquitoes. The sepals are longer than the petals and usually have a long, thin extension on their end. The dorsal sepal is broader than the lateral ones and sometimes forms a hood over the column. The lateral sepals project forward beneath the labellum and the petals spread widely or curve backwards against the ovary. The labellum is heart-shaped and has a prominent callus. The fruit is a thin-walled, glabrous capsule, containing a large number of winged seeds. [2] [4] [8] [9]

Taxonomy and naming

The genus was first formally described by Robert Brown in 1810 in Prodromus Florae Novae Hollandiae . He described three species ( A. fornicatus , A. exsertus and A. caudatus ) but did not nominate a type species. [10] [11] Orchids in this genus are closely related to those in the genus Caladenia . [3] Some Australian species included in Acianthus were at one time transferred to Acianthella, but are now accepted in Acianthus. [12] [13]

The genus name (Acianthus) is derived from the Greek ake or akis, "a point, needle" and anthos "flower" referring to the pointed perianth and the acuminate floral segments. [14] [15]

Species

The following is a list of Acianthus species accepted by Australian Plant Census as at March 2022, apart from A. sinclairii that is accepted by the New Zealand Plant Conservation Network: [13] [15]

Plants of the World Online considers A. apprimus , A. borealis , A. collinus , A. exiguus to be synonyms of A. fornicatus and in addition accepts two further species: [12]

Distribution and habitat

Of the Australian species of Acianthus, 7 are found in New South Wales, 6 in Queensland, 3 in Victoria and 2 in South Australia. The sole New Zealand example, A. sinclairii occurs on both North and South Islands, as well as on Raoul, Stewart, Chatham and Three Kings Islands. [6] [15]

Mosquito orchids species grow in small groups in forests on decaying litter, occasionally on partially decayed logs. They sometimes form dense vegetative colonies, in sheltered forest or heathland, and are often found underneath shrubs and bracken. [3]

Ecology

The labellum of Acianthus species produces a sweet nectar which is contained in a sunken area at the base of the labellum. The flowers of Australian species open in sequence up the flowering spike, each flower open for a few days, and are pollinated by fungus gnats from the families Anisopodidae, Sciaridae and Mycetophilidae. Usually only a small percentage of the plants in a colony have flowers. Flies on Acianthus caudatus have been observed to move up the labellum, probing with their proboscis until they reach the nectar, where the up and down "pumping" action of their bodies brings them into contact with the viscidium and pollinia which then adhere to the insect's body. When these are carried to another flower, a similar action causes the pollinia to attach to the receptive stigma. [2] [4] [6] [9]

Use in horticulture

Mosquito orchids are easy to grow in plastic or ceramic pots. They need to be watered regularly except when dormant over summer and to be repotted every one or two years. [6] [17]

Related Research Articles

<i>Cyrtostylis</i> Genus of plants

Cyrtostylis, commonly known as gnat orchids, is a genus of five or six species of flowering plants in the orchid family Orchidaceae and is native to Australia and New Zealand. Cyrtostylis orchids often form dense colonies of genetically identical plants. They have a single heart-shaped leaf and a thin flowering stem with pale coloured insect-like flowers. The lateral sepals and petals are similar in size and colour but the labellum is shelf-like and conspicuous with two prominent glands at its base.

<i>Liparis</i> (plant) Genus of plants

Liparis, commonly known as widelip orchids, sphinx orchids or 羊耳蒜属 is a cosmopolitan genus of more than 350 species of orchids in the family Orchidaceae. Plants in this genus are terrestrial, lithophytic or epiphytic herbs with a wide range of forms. The flowers are usually resupinate and small to medium sized, yellow, yellow-green or purplish with spreading sepals and petals. The labellum is usually larger than the sepals and petals and is lobed, sometimes with a toothed or wavy margin and one or two calli at its base.

<i>Dipodium</i> Genus of orchids

Dipodium, commonly known as hyacinth orchids, is a genus of about forty species of orchids native to tropical, subtropical and temperate regions of south-east Asia, New Guinea, the Pacific Islands and Australia. It includes both terrestrial and climbing species, some with leaves and some leafless, but all with large, often colourful flowers on tall flowering stems. It is the only genus of its alliance, Dipodium.

<i>Eriochilus</i> Genus of orchids

Eriochilus, commonly known as bunny orchids, is a genus of flowering plants in the orchid family, Orchidaceae that is endemic to Australia. Orchids in this genus are distinguished from those in the similar Caladenia by having a glabrous leaf and a densely woolly labellum. Species occur in south-west Western Australia, South Australia, Queensland, New South Wales, the Australian Capital Territory, Victoria, and Tasmania. Their common name alludes to their prominent ear-like lateral sepals.

<i>Dendrobium tetragonum</i> Species of orchid

Dendrobium tetragonum, commonly known as the tree spider orchid, is a variable species of epiphytic or lithophytic orchid endemic to eastern Australia. Tree spider orchids are unusual in having pendulous pseudobulbs that are thin and wiry near the base then expand into a fleshy, four-sided upper section before tapering at the tip. There are only a few thin but leathery leaves at the end of the pseudobulbs and up to five flowers on relatively short flowering stems. To allow for the variations in the species there are five subspecies and a variety, some with a unique common name.

<i>Calochilus</i> Genus of orchids

Calochilus, commonly known as beard orchids, is a genus of about 30 species of plants in the orchid family, Orchidaceae. Beard orchids are terrestrial herbs with a single leaf at the base of the plant, or no leaves. Their most striking feature is a densely hairy labellum, giving rise to their common name. Beard orchids, unlike some other Australian orchids, do not reproduce using daughter tubers, but self-pollinate when cross-pollination has not occurred. Most species occur in Australia but some are found in New Zealand, New Guinea and New Caledonia.

<i>Acianthus fornicatus</i> Species of flowering plant

Acianthus fornicatus, commonly known as bristly mosquito orchid or pixie caps, is a species of flowering plant in the orchid family Orchidaceae and is endemic to eastern Australia. It is a terrestrial herb with a single, heart-shaped leaf and up to ten translucent pinkish-red flowers, and is widespread and common in coastal and near-coastal areas.

<i>Caleana</i> Genus of flowering plants

Caleana, commonly known as duck orchids, is a genus of flowering plants in the orchid family, Orchidaceae that is found in Australia and New Zealand. The Australian species are found in all states but have not been recorded in the Northern Territory. Duck orchids have a single leaf and one or a few, dull-coloured, inconspicuous flowers. Most species are found in Western Australia but one species occurs in eastern Australia and one occurs in eastern Australia and New Zealand. Orchids in this genus as well as the hammer orchids (Drakaea) are pollinated by male thynnid wasps.

<i>Acianthus amplexicaulis</i> Species of flowering plant

Acianthus amplexicaulis, is a species of flowering plant in the orchid family Orchidaceae and is native to eastern Australia and New Caledonia. The Australian Plant Census accepts the name Stigmotodactylus amplexicaulis(F.M.Bailey) S.P.Lyon, M.A.Clem. & D.L.Jones and the National Herbarium of New South Wales Acianthella amplexicaulis(F.M.Bailey) D.L.Jones and M.A.Clem. It is a terrestrial herb with a single leaf and between 2 and 20 translucent green flowers.

<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.

<i>Acianthus apprimus</i> Species of flowering plant

Acianthus apprimus, commonly known as early mosquito orchid, is a species of flowering plant in the orchid family Orchidaceae and is endemic to New South Wales in Australia. It is a terrestrial herb with a single, heart-shaped leaf and between two and nine translucent pinkish flowers with reddish markings and is found in disjunct populations around the state.

Acianthus borealis, commonly known as northern mosquito orchid, is a species of flowering plant in the orchid family Orchidaceae and is endemic to Queensland in Australia. It is a glabrous, terrestrial herb with a single, heart-shaped leaf and between two and twenty transparent pinkish flowers with reddish markings and is widely distributed on the eastern tablelands.

<i>Acianthus collinus</i> Species of flowering plant

Acianthus collinus, commonly known as hooded mosquito orchid or inland mosquito orchid, is a species of flowering plant in the orchid family Orchidaceae and is endemic to south-eastern continental Australia. It is a terrestrial herb with a single, heart-shaped leaf and between two and nine translucent pinkish flowers with reddish markings and is found growing in colonies on sheltered slopes in open forest in on the western slopes of the Great Dividing Range.

<i>Acianthus exiguus</i> Species of flowering plant

Acianthus exiguus, commonly known as tiny mosquito orchid, is a flowering plant in the orchid family Orchidaceae and is endemic to New South Wales in Australia. It is a terrestrial herb with a single, heart-shaped leaf and up to five translucent greenish-white flowers with pinkish markings and is found growing in forests on the north coast of the state.

<i>Acianthus exsertus</i> Species of flowering plant

Acianthus exsertus, commonly known as gnat orchid or large mosquito orchid, is a species of flowering plant in the orchid family Orchidaceae and is endemic to eastern Australia. It is a terrestrial herb with a single, heart-shaped leaf and up to 25 small, fine, dark brown flowers with pinkish and purplish markings and is found growing in sheltered places in forests in Queensland, New South Wales the ACT and Victoria.

<i>Acianthus pusillus</i> Species of flowering plant

Acianthus pusillus, commonly known as small mosquito orchid, is a species of flowering plant in the orchid family Orchidaceae and is endemic to eastern Australia. It is a terrestrial herb with a single, heart-shaped leaf and up to 18 small, translucent green or pinkish flowers with reddish marking and a green to reddish-purple labellum. It is widely distributed, growing in moist places from central-eastern Queensland, south through New South Wales and Victoria to South Australia and Tasmania.

<i>Acianthus caudatus</i> Species of flowering plant

Acianthus caudatus, commonly known as mayfly orchid, is a species of flowering plant in the orchid family Orchidaceae and is endemic to eastern Australia. It is a terrestrial herb with a single egg-shaped or heart-shaped leaf and up to nine dark purplish flowers with thin, spreading sepals and petals, often with a musty odour.

<i>Acianthus cuneatus</i> Species of flowering plant

Acianthus cuneatus, commonly known as New England mosquito orchid, is a species of flowering plant in the orchid family Orchidaceae and is endemic to the Northern Tablelands of New South Wales. It is a terrestrial herb with a single, heart-shaped leaf and up to seven translucent greenish flowers with purplish stripes and is found growing in sheltered slopes in open forest.

Acianthus ledwardii was a species of flowering plant in the orchid family Orchidaceae and was endemic to Queensland in Australia but is now presumed extinct. It was a terrestrial herb with a single, heart-shaped leaf and between 2 and 6 transparent, reddish brown flowers.

<i>Acianthus saxatilis</i> Species of flowering plant

Acianthus saxatilis is a species of flowering plant in the orchid family Orchidaceae and is endemic to Queensland. It is a terrestrial herb with a single, relatively large, heart-shaped leaf and usually up to 5 translucent greenish-brown to greenish-yellow flowers.

References

  1. 1 2 "Acianthus". Australian Plant Census. Retrieved 11 November 2022.
  2. 1 2 3 Jones, David L. (2006). A complete guide to native orchids of Australia including the island territories. Frenchs Forest, N.S.W.: New Holland. p. 161. ISBN   1-877069-12-4.
  3. 1 2 3 Hoffman, Noel; Brown, Andrew (1984). Orchids of south-west Australia (2 ed.). Nedlands, W.A.: University of Western Australia Press. p. 189. ISBN   0855642262.
  4. 1 2 3 Bishop, Anthony (1996). Field guide to the orchids of New South Wales and Victoria. Sydney: UNSW Press. p. 172. ISBN   086840375X.
  5. ↑ Backhouse, Gary; Jeanes, Jeffrey (1995). The orchids of Victoria (1st ed.). Carlton, Vic.: Miegunyah Press. ISBN   052284393X.
  6. 1 2 3 4 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. 68–70. ISBN   0198507100.
  7. ↑ "Acianthus". Royal Botanic Gardens Sydney: plantnet. Retrieved 9 June 2016.
  8. 1 2 "Acianthus". Government of South Australia: efloraSA. Retrieved 9 June 2016.
  9. 1 2 3 "Acianthus". Australian National Botanic Gardens. Retrieved 12 June 2016.
  10. ↑ "Acianthus". APNI. Retrieved 16 September 2019.
  11. ↑ Brown, Robert (1810). Prodromus Florae Novae Hollandiae. London. pp. 321–322. Retrieved 9 June 2016.
  12. 1 2 "Acianthus R.Br." Plants of the World Online . Royal Botanic Gardens, Kew . Retrieved 6 December 2023.
  13. 1 2 "Acianthus R.Br". Australian Plants Census. Retrieved 12 March 2022.
  14. ↑ Quattrocchi, Umberto (2000). CRC world dictionary of plant names : common names, scientific names, eponyms, synonyms, and etymology (Volume 1). CRC Press. p. 30. ISBN   0849326737.
  15. 1 2 3 "Acianthus sinclairii". New Zealand Plant Conservation Network. Retrieved 12 March 2022.
  16. ↑ "Stigmatodactylus amplexicaulis". Australian Plant Census. Retrieved 6 March 2023.
  17. ↑ Jones, David L. (2006). A complete guide to native orchids of Australia including the island territories. Frenchs Forest, N.S.W.: New Holland. p. 301. ISBN   1-877069-12-4.
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