Thelymitra

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Sun orchids
Thelymitra benthamiana.jpg
Leopard orchid Thelymitra benthamiana near Mount Chudalup
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Monocots
Order: Asparagales
Family: Orchidaceae
Subfamily: Orchidoideae
Tribe: Diurideae
Subtribe: Thelymitrinae
Genus: Thelymitra
J.R.Forst. & G.Forst. [1]
Type species
Thelymitra longifolia
J.R.Forst. & G.Forst.
Species
List of Thelymitra species
Synonyms [1]
  • Macdonaldia Gunn ex Lindl.
  • Thelymitra sect. Macdonaldia(Gunn ex Lindl.) Hook.f.
  • ThelymitraJ.R.Forst. & G.Forst. sect. Thelymitra

Thelymitra, commonly known as sun orchids, is a genus of more than 100 species of plants in the orchid family, Orchidaceae. Unlike most other orchids, sun orchids lack a highly modified labellum and all three petals are similar in size, shape and colour. The column is, however, highly modified and usually has prominent wings or glands which are helpful in identifying the species. Most sun orchids close their flowers at night, in cloudy or cool weather, giving rise to their common name. The scientific name means "woman's hood" and refers to the hooded column present in most, but not all species. Most species are endemic to Australia although some are found as far from there as the Philippines and Indonesia. The type species, Thelymitra longifolia , the first to be formally described, was collected in New Zealand.

Contents

Description

Orchids in the genus Thelymitra are terrestrial, perennial, deciduous, sympodial herbs usually with a few inconspicuous, fine roots and a pair of oval-shaped tubers. A single leaf emerges from near the base of the plant and surrounds the lower part of the flowering stem. [2] [3]

The inflorescence is a raceme with from one to many resupinate flowers with three sepals and three petals all more or less alike in size, shape and ornamentation. (The labellum is not highly modified as in most other orchid genera but is similar to the other two petals.) The sexual parts of the flower are fused to the column which is short and stubby with wings which surround the column, forming a hood-like "mitra". The dorsal part of the mitra is usually ornamented, with a flat midsection and two side arms. The lower part of the mitra forms an unornamented rim below the column. The flowers of most species only open in bright warm sunlight and close at night or during cold or cloudy weather. A few species self pollinate and their reaction to environmental change is not as apparent. The fruit that follows flowering is a non-fleshy, dehiscent capsule containing up to 500 seeds. [2] [3] [4]

Taxonomy and naming

Joseph Banks collected specimens of Thelymitra longifolia on the North Island of New Zealand during Cook's first expedition to the South Pacific but the first formal description of that species was made by Johann Forster and his son Georg during Cook's second expedition to Australia. They made their collections on the South Island of New Zealand. [5] Thelymitra longifolia is therefore the type species. [6] [7]

In 1803, Robert Brown collected T. venosa from Port Jackson and was the first to formally describe it in 1810. [8] [9] [10]

The name "Thelymitra" is derived from the Ancient Greek words thelys meaning "belonging to women" [11] : 862  and mitra meaning "headdress" or "turban" [11] : 183  referring to the hooded column.

Distribution and habitat

There are about 100 species distributed in higher rainfall areas of Australia, 15 in New Zealand, 11 of which are endemic, one in New Caledonia, one in East Timor and one in Java and the Philippines. Australian species grow in a range of habitats from swamps to relatively dry sandplains. They are common around granite boulders where they benefit from runoff. [4] The New Zealand species grow in boggy places and on clay banks [12] and T. javanica grows on sparsely vegetated mountain slopes. [13] [14]

Ecology

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 pollinators. [15] 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 .

Conservation

Several species are considered by the IUCN as endangered ( T. epipactoides ) or critically endangered ( T. gregaria , T. hiemalis and T. × mackibbinii ). [16]

Use in horticulture

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 mycorrhizal fungi that support the orchid. Due to the buds only opening in warm weather, it is common practice to induce flowering by using a bank of strong incandescent lights to simulate the warm sun. Some work has gone into growing hybrids for better growing and more colour. [17]

Species

See List of Thelymitra species

Related Research Articles

<i>Thelymitra cyanea</i> Species of orchid

Thelymitra cyanea, commonly known as the veined sun orchid in Australia and as the swamp sun orchid or striped sun orchid in New Zealand, is a species of orchid which is native to New Zealand and south-eastern Australia. It has a single erect, fleshy, channelled leaf and up to five bright blue flowers with darker blue veins. It is usually found growing in swamps, sphagnum bogs, and subalpine herbfields, often in clonal colonies.

<i>Thelymitra longifolia</i> Species of orchid

Thelymitra longifolia, commonly called the white sun orchid, common sun orchid or maikuku, is a species of orchid in the family Orchidaceae that is endemic to New Zealand. It was the first of a large number of similar species to be described and is therefore the type species. It has a single grass-like leaf and up to five white flowers

<i>Thelymitra malvina</i> Species of orchid

Thelymitra malvina, commonly called the mauve-tufted sun orchid, is a species of orchid that is native to eastern Australia and New Zealand. It has a single large, fleshy leaf and up to twenty five blue to mauve flowers with pink or mauve tufts on top of the anther.

<i>Thelymitra megacalyptra</i> Species of orchid

Thelymitra megacalyptra, known as Thelymitra megcalyptra in Australia, and commonly known as plains sun orchid, is a species of orchid that is endemic to eastern Australia. It has a single erect, fleshy leaf and up to fifteen blue to purplish, sometimes lilac, pink or white flowers with white tufts on top of the anther.

<i>Thelymitra arenaria</i> Species of orchid

Thelymitra arenaria, commonly called the forest sun orchid, is a species of orchid that is endemic to south-eastern Australia. It has a single long, narrow leaf and up to sixteen purplish self-pollinating flowers which only open on hot days.

<i>Thelymitra basaltica</i> Species of orchid

Thelymitra basaltica, commonly called the grassland sun orchid, is a species of orchid that is endemic to Victoria. It has a single fleshy, channelled, dark green leaf and up to eight small pale blue, self-pollinating flowers which open only slowly on warm to hot days.

Thelymitra bracteata, commonly called the leafy sun orchid or large-bracted sum orchid, is a species of orchid that is endemic to south-eastern Australia. It has a single leathery, more or less flat leaf and up to thirty pale blue flowers that are greenish on the back. The bracts are larger than on similar sun orchids.

<i>Thelymitra brevifolia</i> Species of orchid

Thelymitra brevifolia, commonly called the peppertop sun orchid or short-leaf sun orchid, is a species of orchid that is endemic to south-eastern Australia. It has a single erect, relatively short and broad, dark green leaf and up to twenty purplish or purplish blue flowers. It is a common and widespread self-pollinating species occurring in a wide range of habitats.

Thelymitra exigua, commonly called the short sun orchid, is a species of orchid that is endemic to south-eastern Australia. It has a single fleshy, channelled, dark green leaf and up to eight relatively small pale blue flowers with white toothbrush-like tufts on top of the anther.

Thelymitra cyanapicata, commonly called the dark-tipped sun orchid, is a species of orchid that is endemic to South Australia. It has a single fleshy, linear, channelled leaf and up to three small blue or pale purplish to maroon flowers with a dark purplish blue top of the anther.

Thelymitra pallidiflora, commonly called the pale sun orchid, is a species of orchid that is endemic to Victoria. It has a single erect, channelled, leaf and up to ten white to very pale blue, self-pollinating flowers which only open on hot days.

<i>Thelymitra peniculata</i> Species of orchid

Thelymitra peniculata, commonly called the trim sun orchid, is a species of orchid that is endemic to southern eastern Australia. It has a single long, erect, fleshy, channelled leaf and up to eighteen deep blue to purple self-pollinating flowers.

Thelymitra viridis, commonly called the green sun orchid, is a species of orchid that is endemic to Tasmania. It has a single erect, fleshy, channelled leaf and up to seven small self-pollinating pale blue to pale purplish flowers. The rest of the plant is a pale green colour.

Thelymitra vulgaris, commonly called the slender sun orchid or common sun orchid, is a species of orchid in the family Orchidaceae and endemic to the south-west of Western Australia. It has a single erect, dark green leaf and up to nine relatively small, blue to purplish or white flowers.

Thelymitra xanthotricha, commonly called the yellow tufted sun orchid or yellow tufted slender sun orchid, is a species of orchid in the family Orchidaceae and endemic to the south-west of Western Australia. It has a single erect, fleshy, channelled, dark green leaf and up to six relatively large dark blue to purplish flowers.

Thelymitra lucida, commonly called the glistening sun orchid, is a species of orchid that is endemic to south eastern Australia. It has a single erect, fleshy leaf and up to seven dark blue flowers with the sepals a lighter blue than the petals.

Thelymitra incurva, commonly called the coastal striped sun orchid, is a species of orchid that is endemic to south-eastern Australia. It has a single erect, dark green grass-like leaf and up to seven relatively large, pale blue flowers lacking the darker veins of some other thelymitras, especially the otherwise similar striped sun orchid. It grows in coastal areas of far south-eastern New South Wales and north-eastern Victoria.

<i>Thelymitra venosa</i> Species of orchid

Thelymitra venosa, commonly known as the large veined sun orchid, is a species of orchid that is endemic to New South Wales. It has a single fleshy, channelled leaf and up to six relatively large, bright-blue flowers with darker veins. The arms on the side of the column are twisted and yellow, but not toothed at the tip. Unlike most other thelymitras, the flowers do not usually close on cloudy days.

<i>Thelymitra maculata</i> Species of orchid

Thelymitra maculata, commonly called the spotted curly locks or eastern curly locks, is a species of orchid in the family Orchidaceae and endemic to the south-west of Western Australia. It has a single erect leaf, spiralling around the flowering stem and a single pink or purplish, spotted flower with more or less circular, yellow ear-like arms on the sides of the column.

Thelymitra atronitida, commonly called the black-hooded orchid, is a species of orchid that is endemic to south-eastern Australia. It has a single erect, leathery, leaf and up to eight moderately dark blue, self-pollinating flowers that only open on hot days.

References

  1. 1 2 "Thelymitra". Australian Plant Census. Retrieved 30 July 2021.
  2. 1 2 Bernhardt, Peter H. "Thelymitra". Royal Botanic Garden Sydney: plantnet. Retrieved 16 July 2016.
  3. 1 2 "Thelymitra". FloraBase . Western Australian Government Department of Biodiversity, Conservation and Attractions.
  4. 1 2 Hoffman, Noel; Brown, Andrew (2011). Orchids of South-West Australia (3rd ed.). Gooseberry Hill: Noel Hoffman. pp. 285–286. ISBN   9780646562322.
  5. ↑ Retha Edens-Meier; Peter Bernhardt, eds. (2014). Darwin's orchids then and now. Chicago: University of Chicago Press. p. 173. ISBN   9780226044910.
  6. ↑ "Thelymitra". APNI. Retrieved 15 July 2016.
  7. ↑ Forster, Johann R.; Forster, Georg (1775). Characteres generum plantarum, quas in itinere ad insulas maris Australis (1 ed.). London. pp. 97–98. Retrieved 30 July 2021.
  8. ↑ Jeanes, Jeffrey A. (2012). "Two new rare species in the Thelymitra venosa complex (Orchidaceae) from south-eastern mainland Australia". Muelleria. 30 (1): 8.
  9. ↑ "Thelymitra venosa". APNI. Retrieved 15 July 2016.
  10. ↑ Brown, Robert (1810). Prodromus Florae Novae Hollandiae. London. p. 314. Retrieved 15 July 2016.
  11. 1 2 Brown, Roland Wilbur (1956). The Composition of Scientific Words. Washington, D.C.: Smithsonian Institution Press.
  12. ↑ "Sun Orchids". New Zealand Native Orchid Group. Retrieved 19 July 2016.
  13. ↑ "Thelymitra javanica". Internet Orchid Species Photo Encyclopedia. Retrieved 19 July 2016.
  14. ↑ Jeanes, Jeffrey A. (2004). "A revision of the Thelymitra pauciflora R.Br. (Orchidaceae) complex in Australia". Muelleria. 19: 19–79.
  15. ↑ Edens-Meier, Retha M.; Raguso, Robert A.; Westhus, Eric; Bernhardt, Peter (21 March 2014). "Floral Fraudulence: Do Blue Thelymitra Species (Orchidaceae) Mimic Orthrosanthus laxus (Iridaceae)?". Telopea. 17: 15–28. doi: 10.7751/telopea20147392 .
  16. ↑ Coates, Fiona; Jeanes, Jeff; Pritchard, Andrew. "Recovery plan for twenty five threatened orchid taxa of Victoria, South Australia and New South Wales (2003 - 2007)" (PDF). Government of Australia Department of the Environment and Heritage. Retrieved 19 July 2016.
  17. ↑ Nesbitt, Les. "Australia's Native Orchids". Australian Native Plants Society Australia. Retrieved 19 July 2016.
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