Thelymitra
Encyclopedia
Thelymitra is a genus of orchids known as 'sun orchids' in reference to their habit of only opening in warm weather.

Description

They are about 100 species distributed in higher rainfall areas across Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

 (with 50 or so species), New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...

 (10+ endemic species), New Caledonia
New Caledonia
New Caledonia is a special collectivity of France located in the southwest Pacific Ocean, east of Australia and about from Metropolitan France. The archipelago, part of the Melanesia subregion, includes the main island of Grande Terre, the Loyalty Islands, the Belep archipelago, the Isle of...

 (2), Timor
Timor
Timor is an island at the southern end of Maritime Southeast Asia, north of the Timor Sea. It is divided between the independent state of East Timor, and West Timor, belonging to the Indonesian province of East Nusa Tenggara. The island's surface is 30,777 square kilometres...

, Java, and the Philippines
Philippines
The Philippines , officially known as the Republic of the Philippines , is a country in Southeast Asia in the western Pacific Ocean. To its north across the Luzon Strait lies Taiwan. West across the South China Sea sits Vietnam...

.

The type species
Type species
In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...

 is Thelymitra longifolia J.& G. Forst. 1775 from the South Island of New Zealand. The scientific name Thelymitra was given by J. R. and G. Forster, botanists on Captain Cook's second voyage. The genus name is derived from the Greek words thely (woman) and mitra (mitre hat), referring to elaborate shape of the staminodal (staminode = sterile stamen
Stamen
The stamen is the pollen producing reproductive organ of a flower...

) structure at the top of the column
Column (botany)
The column, or technically the gynostemium, is a reproductive structure that can be found in several plant families: Aristolochiaceae, Orchidaceae, and Stylidiaceae....

, called a mitra.

These terrestrial orchids are only above ground during spring and early summer, usually with a single leaf
Leaf
A leaf is an organ of a vascular plant, as defined in botanical terms, and in particular in plant morphology. Foliage is a mass noun that refers to leaves as a feature of plants....

, growing up from two underground tuber
Tuber
Tubers are various types of modified plant structures that are enlarged to store nutrients. They are used by plants to survive the winter or dry months and provide energy and nutrients for regrowth during the next growing season and they are a means of asexual reproduction...

s. It is elongated or linear-lanceolate and glabrous. The Custard Orchid (T. villosa) is the only species with a hairy leaf. The leaves of T. spiralis and T. variegata are spirally twisted.

The flower
Flower
A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants . The biological function of a flower is to effect reproduction, usually by providing a mechanism for the union of sperm with eggs...

 stalk is usually a bluish-green colour. The flower stem usually carries 4 to 10 flowers (even up to 20 flowers in the Plain Sun Orchid, T. holmesii), often opening all at once, though some species have only one flower each year. The flower size is between 1 and 6 cm. These flowers only open in bright sunlight (in combination with warmth and humidity), close at night and during cold or cloudy weather.

Sun orchids exhibit a particular characteristic : their lip
Labellum
Labellum is the Latin diminutive of labium, meaning lip. These are anatomical terms used descriptively in biology, for example in Entomology and botany.-Botany:...

 shows, except in a few species such as T. variegata, almost the same shape, colour, colour pattern or size as the other petals and sepals. This gives a symmetrical shape to the perianth
Tepal
Tepals are elements of the perianth, or outer part of a flower, which include the petals or sepals. The term tepal is more often applied specifically when all segments of the perianth are of similar shape and color, or undifferentiated, which is called perigone...

. Furthermore the lip lacks ornamentation. In other orchid genera, the lip has a distinctive shape and colour. The particular shape and color of the sun orchids mimics the flowers of lily family (Liliaceae) and the family Goodeniaceae, aiming by deceit for the same insect pollinator
Pollinator
A pollinator is the biotic agent that moves pollen from the male anthers of a flower to the female stigma of a flower to accomplish fertilization or syngamy of the female gamete in the ovule of the flower by the male gamete from the pollen grain...

s. The Slender Sun Orchid (T.pauciflora) only opens for a short time (or not at all) and is self-pollinating. This self-pollination is a successful strategy followed by several other species such as and T. circumsepta, T. graminea, T. holmesii and T. mucida.

Once the weather dries out the leaf shrivels away and the orchid lies as a single spherical tuber.

Sun orchids come in most colours, including purple, deep blue (T. pauciflora), white, pink, magenta, maroon, yellow (T. antennifera) and red (T. x macmillanii). Most are a single colour or have spots, a few have stronger variation and are multi-coloured. The deep blue colour, found in about 75% of the sun orchids, is of a rare kind, found only in 5 other orchid genera.

Several species are considered by the IUCN as endangered (T. epipactoides) or critically endangered (T. gregaria, T. hiemalis and T. x mackibbinii. A number of conservation measures are underway in South Australia.

Until shortly, the taxonomy of the genus was outmoded and understudied. Jeffrey A Jeanes of the Royal Botanic Gardens Melbourne
Royal Botanic Gardens, Melbourne
The Royal Botanic Gardens Melbourne are internationally renowned botanical gardens located near the centre of Melbourne, Victoria, Australia, on the south bank of the Yarra River. They are 38 hectares of landscaped gardens consisting of a mix of native and non-native vegetation including over...

 has recently (2004) done a taxonomic revision, resolved several species complexes and described a considerable number of new species (see Muelleria 19; 2004)

Species

  • Thelymitra aemula Cheeseman 1919
  • Thelymitra aggericola D.L.Jones 1999
  • Thelymitra albiflora Jeanes 2004
  • Thelymitra angustifolia R.Br. 1810
  • Thelymitra antennifera (Lindl.) Hook.f. 1858 : Rabbit-eared Sun Orchid, Lemon-scented Orchid, Vanilla Orchid
  • Thelymitra apiculata (A.S.George
    Alex George
    Alexander Segger George is a Western Australian botanist. He is the authority on the plant genera Banksia and Dryandra...

    ) M.A.Clem. & D.L.Jones 1989 : Fine Point Thelymitra
  • Thelymitra arenaria Lindl. 1840
  • Thelymitra aristata Lindl. 1840 : Giant Sun Orchid
  • Thelymitra atronitida Jeanes 2000
  • Thelymitra azurea R.S.Rogers 1917 : Azure Sun Orchid
  • Thelymitra basaltica Jeanes 2004
  • Thelymitra batesii Jeanes 2004
  • Thelymitra benthamiana Rchb.f. 1871 : Bentham's Thelymitra, Leopard Orchid
  • Thelymitra bracteata J.Z.Weber ex Jeanes 2004
  • Thelymitra brevifolia Jeanes 2004
  • Thelymitra campanulata Lindl. 1840 : Bell-shaped Thelymitra, Shirt Orchid
  • Thelymitra canaliculata R.Br. 1810
  • Thelymitra carnea R.Br. 1810 : Flesh-red Thelymitra
  • Thelymitra circumsepta Fitzg. 1878
  • Thelymitra colensoi Hook.f. 1864
  • Thelymitra cornicina Rchb.f. 1871 : Horn-shaped Thelymitra, Lilac Sun Orchid
  • Thelymitra cornuta Colenso 1887 (publ. 1888).
  • Thelymitra crinita
    Thelymitra crinita
    Thelymitra crinita, commonly known as the Blue Lady Orchid, the Queen Orchid, the Lily Orchid or the Long-haired Thelymitra, is a species of orchid which is endemic to the south-west of Western Australia...

    Lindl. 1840 : Long-haired Thelymitra, Blue Lady orchid
  • Thelymitra cucullata Rupp 1946 : Cowl-carrying Thelymitra
  • Thelymitra cyanapicata Jeanes 2004
  • Thelymitra cyanea (Lindl.) Benth. 1873
  • Thelymitra decora Cheeseman 1906
  • Thelymitra dentata L.B.Moore 1968
  • Thelymitra epipactoides F.Muell. 1866
  • Thelymitra erosa D.L.Jones & M.A.Clem. 1998
  • Thelymitra exigua Jeanes 2004
  • Thelymitra flexuosa Endl. 1839 : Bent Thelymitra, Twisted Sun Orchid
  • Thelymitra forbesii Ridl. in H.O.Forbes 1885
  • Thelymitra formosa Colenso 1884
  • Thelymitra fragrans D.L.Jones & M.A.Clem. 1988
  • Thelymitra frenchii Jeanes 2004
  • Thelymitra fuscolutea R.Br. 1810 : Brown-yellow Thelymitra, Chestnut Sun Orchid
  • Thelymitra graminea Lindl. 1840
  • Thelymitra granitora D.L.Jones & M.A.Clem. 1998
  • Thelymitra gregaria D.L.Jones & M.A.Clem. 1998
  • Thelymitra hatchii L.B.Moore 1968
  • Thelymitra hiemalis D.L.Jones & M.A.Clem. 1998
  • Thelymitra holmesii Nicholls 1932 : PLain Sun Orchid
  • Thelymitra imbricata D.L.Jones & M.A.Clem. 1998
  • Thelymitra improcera D.L.Jones & M.A.Clem. 1998
  • Thelymitra inflata Jeanes 2004
  • Thelymitra intermedia Berggr. 1877
  • Thelymitra irregularis Nicholls 1946
  • Thelymitra ixioides
    Thelymitra ixioides
    Thelymitra ixioides, known as the Spotted Sun Orchid is a common plant in eastern and southern Australia. Leaves are thin or lanceolate, up to 20 cm long. A small plant with spotted flowers, forming from August to January. Usually blue, but sometimes violet. It grows in eucalyptus woodland or...

    Sw., 1800 : Spotted Sun Orchid
  • Thelymitra javanica Blume 1825
  • Thelymitra jonesii Jeanes 2001
  • Thelymitra juncifolia Lindl. 1840
  • Thelymitra latiloba Jeanes (2001
  • Thelymitra longifolia J.R.Forst. & G.Forst. 1775
  • Thelymitra longiloba D.L.Jones & M.A.Clem.1998
  • Thelymitra lucida Jeanes 2004
  • Thelymitra luteocilium Fitzg. 1882
  • Thelymitra macrophylla
    Thelymitra macrophylla
    Thelymitra macrophylla, commonly called the Large-leafed Thelymitra, is a species of orchid endemic to western and southwestern Australia....

    Lindl. 1840 : Large-leafed Thelymitra
  • Thelymitra malvina M.A.Clem., D.L.Jones & Molloy 1989
  • Thelymitra matthewsii Cheeseman 1910 (publ. 1911)
  • Thelymitra media R.Br. 1810
    • Thelymitra media var. carneolutea Nicholls 1943
    • Thelymitra media var. media.
  • Thelymitra megacalyptra Fitzg. 1879 : Large-capped Thelymitra
  • Thelymitra merraniae Nicholls 1929
  • Thelymitra mucida Fitzg. 1882
  • Thelymitra nuda R.Br. 1810 : Naked Thelymitra
  • Thelymitra occidentalis Jeanes 2001
  • Thelymitra pallidiflora Jeanes 2004
  • Thelymitra papuana J.J.Sm. 1934 : Papua Thelymitra
  • Thelymitra pauciflora
    Thelymitra pauciflora
    Thelymitra pauciflora, commonly called the Slender Sun Orchid, is a species of orchid which is endemic to Australia. It grows to 50 cm in height and produces grey-blue, blue, white, pink or purple flowers between August and January in its native range.The species was first formally described by...

    R.Br. 1810 : Slender Sun Orchid
  • Thelymitra peniculata Jeanes 2004
  • Thelymitra planicola Jeanes 2000
  • Thelymitra polychroma D.L.Jones & M.A.Clem. 1998
  • Thelymitra psammophila C.R.P.Andrews 1905
  • Thelymitra pulchella Hook.f. 1853
  • Thelymitra purpurata Rupp 1946
  • Thelymitra rubra
    Thelymitra rubra
    Thelymitra rubra, commonly called the Salmon Sun Orchid, is a species of orchid endemic to southeastern Australia....

    Fitzg. 1882 : Salmon Sun Orchid
  • Thelymitra sanscilia H.S.Irwin ex Hatch (1952
  • Thelymitra sarasiniana Kraenzl. in F.Sarasin & J.Roux 1914
  • Thelymitra sargentii R.S.Rogers 1930 : Sargent's Thelymitra
  • Thelymitra silena D.L.Jones 1999
  • Thelymitra simulata D.L.Jones & M.A.Clem. 1998
  • Thelymitra spadicea D.L.Jones & M.A.Clem. 1998
  • Thelymitra sparsa D.L.Jones & M.A.Clem. 1998
  • Thelymitra spiralis (Lindl.) F.Muell. 1865 : Spiral Thelymitra, Curly Locks
    • Thelymitra spiralis var. pulchella Nicholls 1949
    • Thelymitra spiralis var. spiralis
  • Thelymitra stellata Lindl. 1840 : Star-shaped Thelymitra
  • Thelymitra tholiformis Molloy & Hatch 1990
  • Thelymitra tigrina R.Br. 1810 : Tiger-like Striped Thelymitra
  • Thelymitra variegata (Lindl.) P.J.Müll. 1865 : Irregularly Spotted Thelymitra, (Austr.) The Queen of Sheba Orchid
  • Thelymitra venosa R.Br. 1810
  • Thelymitra villosa Lindl. 1840 : Hirsute Thelymitra, Custard Orchid
  • Thelymitra viridis Jeanes 2004
  • Thelymitra vulgaris Jeanes 2004
  • Thelymitra xanthotricha Jeanes 2004

Natural hybrids

  • Thelymitra × chasmogama R.S.Rogers 1927 (T. luteocilium × T. nuda)
  • Thelymitra × mackibbinii F.Muell. 1881 (T. × macmillanii × T. nuda)
  • Thelymitra × macmillanii F.Muell. 1865 (T. antennifera × T. luteocilium)
  • Thelymitra × truncata R.S.Rogers 1917

Cultivation

Thelymitras can be grown in a freely draining, dense mixture with partially composted organic matter. A suitable mixture is an equal mix of 7 mm road screenings, year old composted wood chips and commercial potting mix. It is good practice to cover the surface in pine or she-oak needles to control water loss and to feed the mychorizal fungi that support the orchid.

Due to the flowers only opening in warm weather, it is common practice for showing them, to use a bank of strong incandescent lights to simulate the warm sun.

Some work has gone into growing hybrids for better growing and more colour. The most popular hybrid is probably Th. x "Kay Nesbitt" with its strongly coloured reddish pink flowers.
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