Dipodium variegatum

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Slender hyacinth orchid
Dipodium variegatum inflorescence.jpg
Dipodium variegatum in Meroo National Park
Scientific classification Red Pencil Icon.png
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Monocots
Order: Asparagales
Family: Orchidaceae
Subfamily: Epidendroideae
Genus: Dipodium
Species:
D. variegatum
Binomial name
Dipodium variegatum

Dipodium variegatum, commonly known as the slender hyacinth-orchid, [2] or blotched hyacinth-orchid, [3] is a leafless mycoheterotrophic orchid that is endemic to south-eastern Australia. It forms mycorrhizal relationships with fungi of the genus Russula .

Contents

Description

Dipodium variegatum is a leafless, mycoheterotrophic orchid. For most of the year, it lies dormant and has no above-ground presence; its tubers grow fleshy roots and form shoots consisting of leaf-like, sharply pointed, overlapping bracts, sometimes protruding above the ground, from which inflorescences emerge. The plant blooms in December-February, and the unbranched flowering stem, 15–60 cm (6–20 in) tall, carries 2-50 flowers. The blossoms are fleshy and cream-coloured to light pink with maroon blotches. The sepals and petals are 11–15 mm (0.43–0.59 in) long, 3–5 mm (0.12–0.20 in) wide, and slightly reflexed. The labellum is 6–15 mm (0.2–0.6 in) long and mauve to maroon. There are two diverging linear, hairy keels near the base of the labellum and a band of mauve hairs about 1 mm (0.04 in) long along its midline. The ovaries are curved with a warty surface. Along with the pedicels they are covered in conspicuous maroon spotting and together are 10–17 mm (0.39–0.67 in) long. [3] [4] A form with sepals and petals that are completely dark maroon occurs in some parts of its distribution. [2]

Dipodium variegatum is similar to D. roseum , but the latter species has converging keels on the labellum and lacks the dense patch of tangled hairs near the tip of the labellum of D. variegatum. Also, of the Dipodium species that occur in Australia, D. variegatum is the only to have distinctly spotted ovaries (and sometimes pedicels). [3]

Taxonomy

Dipodium variegatum was first formally described in 1987 by Australian botanists Mark Clements and David Jones and the description was published in Proceedings of the Royal Society of Queensland . The type specimen was collected beside the Pacific Highway in Beenleigh, Queensland. [5] The specific epithet (variegatum) is a Latin word meaning "of different sorts, particularly colors". [6]

Distribution and habitat

Dipodium variegatum occurs in eastern parts of Queensland as far north as the Mount Windsor Tableland west of Daintree National Park and in New South Wales as far west as Temora. In Victoria it is only found in the far east. It grows in a wide range of habitats from heath to wet forests. [4]

Ecology

Recovered DNA shows that this orchid forms mycorrhizal associations with Russula solaris and R. occidentalis , in keeping with the observation that many members of the genus form relationships with fungi of the family Russulaceae. [7] The orchid has been observed to occur in close proximity to Eucalyptus species and it is thought that a relationship exists with these trees through this mycorrhizal association. [8]

Pollination of this species, as for all species in the genus, is by native bees and wasps. [2]

Conservation

The species is listed as "rare" on the Victorian Department of Environment and Primary Industries advisory list of rare or threatened plants in Victoria. [9]

Cultivation

No leafless species of Dipodium has been sustained in cultivation due to the inability to replicate its association with mycorrhizal fungi in a horticultural context. [2]

Related Research Articles

<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>Dipodium punctatum</i> Species of orchid

Dipodium punctatum, commonly known as the blotched hyacinth-orchid, is a leafless orchid that is a native to eastern and south-eastern continental Australia. In summer it produces a tall flowering stem with up to sixty pale to bright pink flowers with heavy red blotches. A widespread and common species it is often confused with D. roseum and some authorities regard it as a synonym of D. squamatum.

<i>Dipodium elegantulum</i> Species of orchid

Dipodium elegantulum, commonly known as the elegant hyacinth orchid, is a leafless orchid that is endemic to Queensland. In spring and summer it has up to sixty pale to dark pink flowers with a few darker spots and streaks near the tips, on a tall flowering stem.

<i>Dendrobium bigibbum</i> Species of orchid from Australia and New Guinea

Dendrobium bigibbum, commonly known as the Cooktown orchid or mauve butterfly orchid, is an epiphytic or lithophytic orchid in the family Orchidaceae. It has cylindrical pseudobulbs, each with between three and five green or purplish leaves and arching flowering stems with up to twenty, usually lilac-purple flowers. It occurs in tropical North Queensland, Australia and New Guinea.

<i>Dipodium roseum</i> Species of orchid

Dipodium roseum, commonly known as rosy hyacinth-orchid or pink hyacinth-orchid, is a leafless saprophytic orchid found in east and south-eastern Australia. In summer it produces a tall flowering stem with up to fifty pale pink flowers with small, dark red spots. A widespread and common species it is often confused with D. punctatum but has darker, less heavily spotted flowers.

<i>Caleana</i>

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>Cryptostylis hunteriana</i>

Cryptostylis hunteriana, commonly known as the leafless tongue-orchid is a flowering plant in the orchid family Orchidaceae and is endemic to south eastern Australia. It is leafless but has up to ten green flowers with a more or less erect, dark reddish brown labellum.

<i>Aphyllorchis queenslandica</i>

Aphyllorchis queenslandica, commonly known as the yellow pauper orchid, is a leafless terrestrial mycotrophic orchid in the family Orchidaceae. It has up to twelve dull yellow flowers on a thin, fleshy, purple flowering stem and is endemic to tropical north Queensland where it grows in rainforest.

<i>Dipodium hamiltonianum</i> Species of orchid

Dipodium hamiltonianum, commonly known as yellow hyacinth-orchid, is a leafless mycoheterotroph orchid that is endemic to eastern Australia. It has up to twenty five greenish flowers with dark red spots on a tall flowering stem.

<i>Dipodium pardalinum</i> Species of orchid

Dipodium pardalinum, commonly known as spotted hyacinth-orchid or leopard hyacinth-orchid, is a leafless hemiparasitic orchid that is endemic to south-eastern Australia.

Dipodium campanulatum, commonly known as the bell-flower hyacinth orchid, is a leafless mycoheterotroph orchid that is endemic to south-eastern Australia. In summer it has up to thirty five white flowers with large, dark red spots and blotches.

<i>Dipodium stenocheilum</i> Species of orchid

Dipodium stenocheilum, commonly known as tropical hyacinth-orchid, is a leafless saprophytic orchid that is endemic to northern Australia. For most of the year the plant is dormant but in summer it produces a tall flowering stem with up to twenty five white flowers with purple spots and a mauve labellum.

<i>Dipodium ensifolium</i> Species of orchid

Dipodium ensifolium, commonly known as leafy hyacinth-orchid, is an orchid species that is endemic to north-east Queensland. It has sword-shaped leaves and up to twenty pink to mauve flowers with purplish spots and blotches.

<i>Dipodium atropurpureum</i> Species of orchid

Dipodium atropurpureum, commonly known as the purple hyacinth orchid, is an almost leafless mycoheterotrophic orchid that is endemic to New South Wales. In summer it has up to forty dark pinkish purple to reddish purple flowers with darker spots and blotches on a tall flowering stem.

Dipodium pulchellum is an almost leafless orchid that is endemic to north-east New South Wales and south-east Queensland in Australia. Up to forty pink flowers with darker blotches are borne in summer and winter on flowering spikes up to 90 cm (40 in) long.

Caladenia atroclavia, commonly known as the black-clubbed spider orchid, is a plant in the orchid family Orchidaceae and is endemic to south-eastern Queensland. It is a ground orchid with a single hairy leaf and a pale greenish-cream coloured flower with dark purple clubs and red patches on the petals.

<i>Caladenia actensis</i>

Caladenia actensis, commonly known as the Canberra spider orchid, is a plant in the orchid family Orchidaceae and is endemic to the Australian Capital Territory. It has a single leaf and usually only one greenish flower with red markings and only occurs in three small populations.

<i>Epipogium roseum</i>

Epipogium roseum, commonly known as the ghost orchid, leafless nodding orchid or 虎舌兰 , is a leafless terrestrial mycotrophic orchid in the family Orchidaceae. It has up to sixteen cream-coloured, yellowish or pinkish flowers with an enlarged ovary on a fleshy hollow flowering stem. This ghost orchid is widely distributed in tropical Africa, Asia, Southeast Asia, New Guinea, Australia and some Pacific Islands.

Gastrodia urceolata, commonly known as white potato orchid, is a leafless terrestrial mycotrophic orchid in the family Orchidaceae. It has a pale brown, fleshy flowering stem and up to fifty five upright, white to pale brown flowers. It is only known from a single population near Atherton in Queensland.

Rhizanthella speciosa is a species of flowering plant in the orchid family and is endemic to Barrington Tops in New South Wales. It is a mycoheterotrophic herb that spends its entire life cycle, including flowering, at or below the soil surface. As at September 2020, R. speciosa has not yet been accepted as a valid name by the World Checklist of Selected Plant Families or the Australian Plant Census.

References

  1. "Dipodium variegatum". World Checklist of Selected Plant Families (WCSP). Royal Botanic Gardens, Kew.
  2. 1 2 3 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. 273. ISBN   9781877069123.
  3. 1 2 3 Jeanes, Jeff. "Dipodium variegatum". Royal Botanic Gardens Victoria. Retrieved 5 February 2019.
  4. 1 2 Weston, Peter H. "Dipodium variegatum". Royal Botanic Garden Sydney. Retrieved 5 February 2019.
  5. "Dipodium variegatum". APNI. Retrieved 5 February 2019.
  6. Brown, Roland Wilbur (1956). The Composition of Scientific Words. Washington, D.C.: Smithsonian Institution Press. p. 265.
  7. Dearnaley, John D.W. (2006). "Fungal endophytes in Australian myco-heterotrophic orchids" (PDF). Eighth International Mycological Congress: 167–170. Retrieved 5 February 2019.
  8. Bougoure, Jeremy J.; Dearnaley, John D.W. (2005). "The fungal endophytes of Dipodium variegatum (Orchidaceae)". Australian Mycologist. 24 (1).
  9. "Threatened species advisory lists". Department of Environment and Primary Industries. Retrieved 23 January 2014.