Diuris

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Donkey Orchids
Diuris 03 gnangarra.jpg
Diuris magnifica
Scientific classification
Kingdom: Plantae
(unranked): Angiosperms
(unranked): Monocots
Order: Asparagales
Family: Orchidaceae
Subfamily: Orchidoideae
Tribe: Diurideae
Subtribe: Diuridinae
Genus: Diuris
Sm., 1798

Diuris is a genus of herbaceous plant belonging to the orchid family (Orchidaceae), with more than fifty described species. The genus is being revised, with many newly described species.

The scientific name is derived from the Greek words dis (double) and oura (tail), referring to the two lateral drooping sepals, giving a tailed appearance. The common name Donkey Orchid is logically derived from the appearance of the two lateral petals, protruding from the top of the flower like the two ears of a donkey. These features give Diuris its easily recognizable appearance.

Diuris consists of perennial species native to open habitats in Australia and Tasmania, with plus one species endemic to Timor.

Many species are common in Australia. They grow in large clusters, due to the vegetative growth of their tubers. The genus is one of the best known of Australian terrestrial orchids with the purple Diuris (D. punctata) being always popular when exhibited.

The basal, grass-like leaves are medium-sized to large. They grow alternately or whorled. Their margins are entire. The central stem can grow up to 1 m high.

During summer, these terrestrial orchids shrivel and wither above the ground. Their underground tubers then become dormant.

The hermaphroditic flowers grow solitary or in several-flowered loose racemes. They can be most diverse, from small (1 cm) to large (6 cm), fragrant or not. Their 3-merous form is usually very irregular. The flowers may be blotched or lacking spots. Their colors vary from a lemon yellow, or yellow and brown, yellow and purple, yellow and orange, to pink and white, or purple. The two lateral petals are rounded or elongated. The dorsal petal forms a hood over the column. The lip is three-lobed. The two lateral lobes form wings.

The flowering period is between July and November.

Pollination is by native, small bees, lured to flowers mimicking flowers of the pea family (Fabaceae), but syrphiid flies and beetles may pollinate as well. The fruit is a non-fleshy, dehiscent capsule, containing between 30 and 500 minute seeds. These seeds mature in a matter of weeks.

Diuris can be grown in a free draining mixture and are relatively easily grown from seed using in-vitro techniques.

The orchids of Diuris are susceptible to the Diuris virus Y, a positive stranded ssRNA virus from the family Potyviridae

Species[edit]

Several Diuris species : nrs. 4 (Diuris carinata) and 12 (Diuris longifolia)

There are several species discovered but not named yet.

Natural hybrids[edit]

  • Diuris × fastidiosa R.S.Rogers 1927 (D. lanceolata × D. palustris)
  • Diuris × nebulosa D.L.Jones 1991 (D. aurea × D. punctata)
  • Diuris × palachila R.S.Rogers 1907 (D. behrii × D. pardina)
  • Diuris × polymorpha Messmer in H.M.R.Rupp, 1944 (D. lanceolata × D. platichila)

References[edit]

  • Jones, David L. (1970). "Some thoughts on the taxonomy of the genus Diuris". Australasian Native Orchid Society.