Diuris

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Read about Diuris in the Standard Cyclopedia of Horticulture 

Diuris (Greek, double-tailed, alluding to the sepals). Orchidaceae. Twenty or more glabrous terrestrial orchids of Austral., rarely seen in collections in cool or warm glasshouses. The lvs. are at or near the base of the bracted st. (which is usually 1-2 ft. high), few, narrow: fls. 1 to several in a terminal raceme, conspicuous from the elongated tail-like lateral green sepals; remainder of perianth yellow, purple or white, sometimes purple-blotched or -spotted; dorsal sepal remaining close to and over the column; lip 3-parted. The species are attractive or even handsome. D. longifolia, R. Br., has fls. several, yellow and purple, moderately large; dorsal sepal broadly ovate, the lateral long and narrow; lip as long as dorsal sepal, lobed from the base: lvs. linear, one of them often very long. D. maculata, Smith, is rather slender, usually under 1 ft. tall, with long-pedicelled yellow much-spotted fls.; dorsal sepal erect and rigid, embracing the column at the base but open at the top; lip shorter than dorsal sepal, lobed from base: Ivs. narrow. B.M. 3156. D. punctata, Smith. St. 1-2 ft. or more: lvs. usually 2, and 3-6 in. long: fls. 2 or 3, blue or purplish, often dotted but not blotched; dorsal sepal typically broadly ovate-oblong; lip about as long as dorsal sepal, divided to base. L. H. B.


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Donkey Orchids
Diuris carinata
Diuris carinata
Plant Info
Scientific classification
Kingdom: Plantae
Division: Magnoliophyta
Class: Liliopsida
Order: Asparagales
Family: Orchidaceae
Subfamily: Orchidoideae
Tribe: Diurideae
Subtribe: Diuridinae
Genus: Diuris
Sm., 1798

Species
See text.


The genus Diuris belongs to the orchid family (Orchidaceae), with more than fifty described species. The genus is presently 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 the exception of 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 cmà 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

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

Species

Diuris drummondii
Diuris longifolia

Furthermore there are several species discovered but not named yet.

Natural hybrids

  • 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)

Reference

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

External links

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