Diuris

Diuris, [die-you-riss.] from dis, double, and oura, a tail; referring to the two lower sepals of the flowers.

orchid illustration 3

An Australian genus known as “Double-tails.” The best known species in Western Australia is commonly called “Donkey Orchid.” Other species of the genus can easily be identified by their resemblance to it in type of flower. Typical characteristics of the genus are the narrow leaves, few at or near the base of the stem, with a few sheathing bracts higher up, the curiously shaped flowers-one, two, or several-in a terminal raceme, the upper sepal short and broad, the two lower sepals narrow and curved, the two upper petals battle-dore shaped, with the lip deeply three-lobed, and total dependance on insects for fertilisation.

Fitzgerald observed that from the compact nature of the pollen masses and the readiness with which they may be moved by the slightest touch of the rostellum, they must be most frequently fertilised by the pollen from other flowers. He noticed an affinity in stigma, rostellum and anther, to Thelymitra ixioides, and produced seed by crossings between this species and Diuris. Many botanists disagree with Bentham’s arrangement of the genus, and consider that he has grouped species in some instances that should have been kept distinct.

Diuris Species in Western Australia

Diuris carinata, “BEE ORCHID”; keel-shaped, referring to the keel-like structure of parts of the flower.
- see Orchid Illustration 3, no 4
Leaves, four or five, awl-shaped Stem about 1 ft. high. Flowers about ¼ in. wide and 1 in. long, yellow, with a purple spot at base and apex of upper sepal and petal. Lip with a double-keeled claw, middle lobe rather closely reduplicate, one-keeled (From description by O.H. Sargent in Journal W.A. Natural History Society.) Favours swampy places and wet clayey flats.
W.A.: Busselton, Darling Range, Highbury, Katanning, Kojonup, Maddington, Pindalup, Toodyay, Wagin, York, September – October.

Diuris emarginata, notched at margin.
A species closely resembling Diuris carinata but taller, stouter and larger flowered Leaves semi terete. Petals without spots, often emarginate. Middle lobe of lip somewhat spreading. Both this species and Diuris carinata inhabit swampy places and flower in October. They often occur together when intermediate forms, which I think must be hybrid, are found among them.” (Description and note by O. H. Sargent, Journal W.A. Natural History Society)
WA: Albany, Harvey, Vaisse River, York. October.

Diuris filifolia, thread-like leaves.
This species and Diuris carinata were not considered distinct by Bentham from Diuris setacea. Dr. Diels (Journal Proceedings Mueller Botanical Society, April, 1903) states: “I am quite sure that these (Diuris setacea, Diuris carinata, and Diuris filifolia) are three different species resembling each other in foliage, but very different in flower. Diuris carinata, Lindley, I believe to be the shorter, stouter plant found in the Darling Range near Perth.” Lindley’s original description states that the stem is much shorter than the sharp-point leaves, flowers yellow, labellum lobed at middle, almost round at base, and one-keeled This species is not recognised as distinct by Dr. Rogers from Diuris carinata
W.A.

Diuris laevis, smooth.
A slender species, 8 in. to 1 ft. high. Leaves from 3 to 6 in. long, numerous, spirally twisted, enclosed at the base by a sheath, Flowers, two to six, light yellow, petals elliptical, about 1 in. long including the dark brown claw. Lateral sepals, linear, green. Upper sepal almost triangular, embracing the column, about half the length of the other sepals. Lip three-lobed, lateral lobes half the length of the central one falcate and toothed along the upper edges, streaked with dark brown; central lobe ovate-rhomboid, linear at base, brown markings. Wings of column same length as column, toothed, (Described “Fitzgerald’s Australian Orchids,” Vol, 2.)
W.A. Albany, Busselton, Gosnells, York. September -October.

Diuris longifolia, “DAMSEL ORCHID ” “DINGO ORCHID” “DONKEY ORCHID” “PANSY ORCHID”; long leaf.
- see Orchid Illustration 3, no 12
From under 1 ft. high to considerably more. Leaves linear, narrow or broad, usually very long. Flowers, three to five, occasionally more, variable in size, yellow and brown, sometimes heavily suffused with purple, when the resemblance to a pansy is marked The two upper petals are often 3/4in or more long, erect, and are supposed to be like the ears of a donkey, lower sepals as long, long, linea or dilated above the middle. Upper sepal short and very broad Lip three-lobe from the base, lateral lobes nearly as long as the middle one, middle lobe contracted into a claw at base, with a fairly prominent line along the centre. A common species favouring all conditions of soil and situation.
W.A.: Widely distributed
New South Wales, South Australia, Tasmania, Victoria.

Diuris pauciflora, few-flowered.
A slender plant, 6 in. to 1 ft. high. Leaves very narrow. Flowers, one to three, yellow and purple. Petals ovate, about 1/2 in. long, including the very short claw, lateral sepals not reflexed, linear, but rather broader than in most species. Upper sepal shorter. Lip three-lobed from the base, lateral lobes not half as long as middle lobe, with a slight central raised line not half the length of lip. Favours wet sandy flats.
W.A.: Albany, Kalamunuda, Mt. Barker. October – November.

Diuris Purdiei, honouring Alexander Purdie, M.A.
A small species 6 or 8 in. high. Leaves narrow-linear, 2½ to 3 in. long. Upper sepal shorter than the lateral petals, lateral sepals pointed, longer than the lip. Lateral petals with a long claw, elliptical, yellow with purple veins, Lip three-lobed, with two short raised lines, middle lobe large, almost rhomboid, much longer than the small half-ovate lateral lobes, which are deeply cleft on the outer side. Easily recognised by the narrow leaves and by the lip very different to other narrow-leaved Diuris species. (Described Journal Proceedings Mueller Botanical Society, April, 1903). Favours wet sandy flats.
W.A.: Bridgetown, Cannington, Pinjarra. October.

Diuris setacea, bristly.
Leaves 8 to 10, linear, spirally twisted Flowers sulphur yellow. Lip with a single keel from base to apex, middle lobe somewhat spreading (From description by
O. H. Sargent, in Journal W.A. Natural History Society). Favours loam and clay soil.
W.A.: Albany, Dumbleyung, Jarrahdale, Katanning, Pindalup, Pinjarra October- November.

West Australian Orchids Series

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Diuris

Diuris Species in Western Australia

West Australian Orchids Series

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