Dipodium, commonly known as hyacinth orchids,[3] 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.
Description
Orchids in the genus Dipodium are perennial, terrestrial herbs or climbers/epiphytes. Many species, particularly in eastern Australia are leafless mycoheterotrophs. Others have medium-sized to very large leaves that are parallel-veined and have entire margins. The flowers are arranged in a raceme with very few or up to fifty large, often colourful flowers. These may be fragrant or odourless, are white, pink, purple, yellow or green, often with spots or blotches. The sepals and petals are free from and similar to each other. The labellum projects forwards and has three lobes with a central band of colourful hairs. Each flower has two pollinia that are supported on two stipes. Dehiscent capsules, produced after flowering, hold the seed which is released when the capsule splits longitudinally along six seams. Between 30 and 500 seeds are produced per capsule.[3][4][5][6]
Taxonomy
The genus was formally described in 1810 by Scottish botanist Robert Brown in Prodromus Florae Novae Hollandiae et Insulae Van Diemen.[1][7] The name Dipodium is derived the Greek words di (two) and podia (little feet), a reference to the two stipes supporting the pollinia.[8]
Two flowering scapes of a leafless species in south-eastern Australia
Distribution and habitat
Hyacinth orchids are found in Malaysia, the Philippines, Indonesia, the Solomon Islands, the New Hebrides, New Caledonia, New Guinea and Australia where eleven species are endemic. They occur in a range of habitats from coastal lowlands to ranges and tablelands.[3][9]
Ecology
It is thought that the flowers attract native bees and wasps through floral mimicry.[10]
Uses
An infusion of the leaves of Dipodium pandanum is traditionally drunk in Bouganville to help relieve respiratory infections.[11]
Use in horticulture
Leafless hyacinth orchids are impossible to grow in cultivation but D. pandanum is easy to grow in warm climates.[3]: 272
Species
The following is a list of described species in the genus Dipodium, recognised by the World Checklist of Selected Plant Families[2] apart from Dipodium punctatum which is recognised as a species in Australia (rather than as a synonym of Dipodium squamatum).[1][12]
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Dipodium ambiguum - from Malesia
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Dipodium atropurpureum - purple hyacinth orchid, from New South Wales
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Dipodium bicallosum - from Peninsular Malaysia and Sumatra
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Dipodium bicarinatum - from Peninsular Malaysia
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Dipodium brassii - from Papua New Guinea
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Dipodium brevilabium - from Western Papua
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Dipodium campanulatum - bell-flower hyacinth-orchid, from South Australia and Victoria
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Dipodium chanii - from Borneo
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Dipodium conduplicatum - from Peninsular Malaysia and Sumatra
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Dipodium confusum - from Borneo
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Dipodium elatum – from Sumatra
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Dipodium elegans - from Sumatra
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Dipodium elegantulum - elegant hyacinth-orchid, from Queensland
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Dipodium ensifolium - leafy hyacinth-orchid, from north-east Queensland
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Dipodium fevrellii - from Sulawesi
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Dipodium fragrans - from Sumatra, Peninsular Malaysia, Borneo and Sulawesi
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Dipodium freycinetioides - from Palau
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Dipodium gracile - from Sulawesi
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Dipodium hamiltonianum - yellow hyacinth-orchid, from Queensland, New South Wales, the A.C.T. and Victoria
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Dipodium javanicum - from West Java
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Dipodium lambii - from Borneo
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Dipodium meijeri - from Borneo
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Dipodium moultonii - from Borneo
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Dipodium paludosum - from Cambodia, Thailand, Vietnam, The Philippines, Sumatra, Peninsular Malaysia and Borneo
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Dipodium pandanum – Maluku to Papuasia and Queensland
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Dipodium pardalinum - spotted hyacinth-orchid or leopard hyacinth-orchid, from South Australia and Victoria
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Dipodium parviflorum - from Peninsular Malaysia and Sumatra
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Dipodium pictum - from Malesia and the Cape York Peninsula in Queensland
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Dipodium pulchellum - from New South Wales and Queensland
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Dipodium punctatum - blotched hyacinth-orchid or hyacinth orchid, from New South Wales, the A.C.T., Victoria, and South Australia
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Dipodium purpureum - from Borneo
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Dipodium robertyongii - from Borneo
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Dipodium roseum - rosy hyacinth-orchid or pink hyacinth-orchid, from Queensland, New South Wales, the A.C.T., Victoria, South Australia and Tasmania
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Dipodium scandens - from Borneo, Java, The Philippines, Sulawesi, New Guinea, the Bismark Archipelago and the Solomon Islands
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Dipodium speciosum - from Peninsular Malaysia
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Dipodium squamatum - from New Caledonia and Vanuatu
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Dipodium stenocheilum - tropical hyacinth-orchid, from the northern parts of Western Australia, the Northern Territory and Queensland.
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Dipodium variegatum - blotched hyacinth-orchid or slender hyacinth-orchid, from Queensland, New South Wales and Victoria
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Dipodium wenzelii - from Borneo
Undescribed species
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Dipodium sp. Basalt Woodland (M.D. Barrett 198) - northern Kimberley, Western Australia.[13]
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Dipodium sp. Sandstone (R.L. Barrett & K.W. Dixon 1642) - northern Kimberley,[14]
References
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^ a b c d "Dipodium". APNI. Retrieved 12 July 2018.
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^ a b "Dipodium". World Checklist of Selected Plant Families (WCSP). Royal Botanic Gardens, Kew. Retrieved 12 July 2018.
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^ a b c d Jones, David L. (2006). A complete guide to native orchids of Australia including the island territories. Frenchs Forest, N.S.W.: New Holland. p. 270. ISBN 1877069124.
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^ "Dipodium R.Br". FloraBase. Western Australian Government Department of Biodiversity, Conservation and Attractions.
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^ Weston, P.H. "Genus Dipodium". PlantNET - New South Wales Flora Online. Royal Botanic Gardens & Domain Trust, Sydney Australia. Retrieved 7 February 2014.
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^ Jeanes, Jeff. "Dipodium". Royal Botanic Gardens Victoria. Retrieved 12 July 2018.
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^ Brown, Robert (1810). Prodromus Florae Novae Hollandiae et Insulae Van Diemen. London. pp. 330–331. Retrieved 12 July 2018.
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^ Clements, Mark A (2013). The Allure of Orchids. National Library Australia. pp. 48–51. ISBN 978-0-642-27807-4.
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^ Jones, David L. (1991). "New taxa of Australian Orchidaceae". Australian Orchid Research. 2: 48.
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^ Jessup, Scott. "Action statement - yellow hyacinth orchid Dipodium hamiltonianum" (PDF). The State of Victoria, Department of Sustainability and Environment. Retrieved 12 July 2018.
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^ Lawler, L.J.; Slaytor, M. (1969). "The distribution of alkaloids in orchids from the territory of Papua and New Guinea". Proceedings of the Linnean Society of New South Wales. 94: 240. Retrieved 8 February 2014.
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^ "Dipodium punctatum". World Checklist of Selected Plant Families (WCSP). Royal Botanic Gardens, Kew. Retrieved 12 July 2018.
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^ "Dipodium sp. Basalt Woodland (M.D. Barrett 198)". FloraBase. Western Australian Government Department of Biodiversity, Conservation and Attractions.
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^ "Dipodium sp. Sandstone (R.L. Barrett & K.W. Dixon 1642)". FloraBase. Western Australian Government Department of Biodiversity, Conservation and Attractions.
