''Dipodium roseum'', commonly known as rosy hyacinth-orchid or pink hyacinth-orchid, is a leafless saprophytic

orchid Orchids are plants that belong to the family Orchidaceae (), a diverse and widespread group of flowering plants with blooms that are often colourful and fragrant. Along with the Asteraceae, they are one of the two largest families of flowering ...

found in east and south-eastern

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

. 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.

Description

''Dipodium roseum'' is a leafless,

tuber Tubers are a type of enlarged structure used as storage organs for nutrients in some plants. They are used for the plant's perennation (survival of the winter or dry months), to provide energy and nutrients for regrowth during the next growing ...

ous,

perennial A perennial plant or simply perennial is a plant that lives more than two years. The term ('' per-'' + '' -ennial'', "through the years") is often used to differentiate a plant from shorter-lived annuals and biennials. The term is also wide ...

, mycoheterotrophic

herb In general use, herbs are a widely distributed and widespread group of plants, excluding vegetables and other plants consumed for macronutrients, with savory or aromatic properties that are used for flavoring and garnishing food, for medicinal ...

. Between fifteen and fifty pale pink flowers with small dark red spots and wide are borne on a green to dark reddish black flowering stem tall. The

sepal A sepal () is a part of the flower of angiosperms (flowering plants). Usually green, sepals typically function as protection for the flower in bud, and often as support for the petals when in bloom., p. 106 The term ''sepalum'' was coined b ...

s and

petal Petals are modified Leaf, leaves that surround the reproductive parts of flowers. They are often advertising coloration, brightly colored or unusually shaped to attract pollinators. All of the petals of a flower are collectively known as the ''c ...

s are linear to elliptic, long, wide and free from each other with their tips curved backwards. The labellum is pink with dark lines, long, wide and has three lobes with their tips turned upwards. The centre lobe has a broad band of pink to mauve hairs. A rare white-flowering form also exists. Flowering occurs from November to February. This orchid is often confused with ''D. punctatum''. ''D. roseum'' has a broader band of hairs and striping on its labellum, smaller spots and much more recurved sepals and petals. ''D. punctatum'' lacks striping on its labellum, has much more pronounced spotting, and has flat or barely recurved sepals and petals.

Taxonomy and naming

''Dipodium roseum'' was first formally described in 1991 by David Jones and Mark Clements and the description was published in ''Australian Orchid Research''. The

type specimen In biology, a type is a particular wiktionary:en:specimen, specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally attached. In other words, a type is an example that serves to a ...

was collected in Montrose in Victoria's

Dandenong Ranges The Dandenong Ranges (commonly just The Dandenongs) are a set of low mountain ranges, rising to 633 metres at Mount Dandenong, approximately east of Melbourne, Victoria, Australia. The ranges consist mostly of rolling hills, steeply weathere ...

. The

specific epithet In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bot ...

(''roseum'') is a

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

word meaning "rose-coloured", referring to the colour of the flowers of this orchid. The species was previously included in a wider circumscription of ''

Dipodium punctatum ''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 fl ...

''.

Distribution and habitat

The rosy hyacinth orchid grows in a range of habitats from dry woodland to wet forests. It occurs in

Queensland ) , nickname = Sunshine State , image_map = Queensland in Australia.svg , map_caption = Location of Queensland in Australia , subdivision_type = Country , subdivision_name = Australia , established_title = Before federation , established_ ...

south from Gympie, on the coast and ranges of

New South Wales ) , nickname = , image_map = New South Wales in Australia.svg , map_caption = Location of New South Wales in AustraliaCoordinates: , subdivision_type = Country , subdivision_name = Australia , established_title = Before federation , es ...

and the

Australian Capital Territory The Australian Capital Territory (commonly abbreviated as ACT), known as the Federal Capital Territory (FCT) until 1938, is a landlocked federal territory of Australia containing the national capital Canberra and some surrounding townships. ...

and in most of

where it is the most common ''

Dipodium ''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 ...

''. It is also found in the south-east of

South Australia South Australia (commonly abbreviated as SA) is a state in the southern central part of Australia. It covers some of the most arid parts of the country. With a total land area of , it is the fourth-largest of Australia's states and territories ...

and is the only member of the

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

to occur in

Tasmania ) , nickname = , image_map = Tasmania in Australia.svg , map_caption = Location of Tasmania in AustraliaCoordinates: , subdivision_type = Country , subdi ...

Ecology

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

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.

References

{{Taxonbar, from=Q5280027 roseum Endemic orchids of Australia Orchids of New South Wales Orchids of the Australian Capital Territory Orchids of Queensland Orchids of South Australia Orchids of Victoria (state) Orchids of Tasmania