{{Short description|Genus of orchids}} {{Automatic taxobox | image = Thelasis carinata, the Keeled Thelasis (14360664511).jpg | image_caption = ''Thelasis carinata'' | display_parents = 3 | taxon = Thelasis | authority = Blume<ref name="PoWO">{{cite web |title=''Thelasis'' |url=https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:30796-1 |publisher=Plants of the World Online |access-date=23 October 2025}}</ref> | synonyms_ref = <ref name="PoWO"/> | synonyms = * ''Euproboscis'' <small>Griff.</small> * ''Oxyanthera'' <small>Brongn. in L.I.Duperrey</small> * ''Rhynchophreatia'' <small>(Schltr.) Schltr.</small> }}
'''''Thelasis''''', commonly known as '''fly orchids''',<ref name="Jones">{{cite book|last1=Jones|first1=David L.|title=A complete guide to native orchids of Australia including the island territories|date=2006|publisher=New Holland|location=Frenchs Forest, N.S.W.|isbn=1877069124|page =476}}</ref> is a genus of flowering plants from the orchid family, Orchidaceae. Plants in this genus are usually epiphytes, sometimes lithophytes or rarely terrestrials. Some species have pseudobulbs with up to three leaves, whilst others have several leaves in two ranks. A large number of small, white or greenish yellow flowers are borne on a thin, arching flowering stem. There are about thirty species, distributed from tropical and subtropical Asia to the southwest Pacific.
==Description== Plants in the genus ''Thelasis'' are mostly epiphytic or lithophytic, rarely terrestrial sympodial herbs with thin roots. They often have small pseudobulbs with up to three leaves but sometimes have flattened stems with several leaves in two ranks. Many small white or greenish yellow flowers are crowded on a thin arching flowering stem. The flowers are resupinate, tube-shaped near the base with sepals and petals free from and similar to each other although with the petals usually shorter and narrower. The labellum is stiffly attached to the base of the column and lacks lobes.<ref name="Jones" /><ref name="ONG">{{cite web |title=Genus ''Thelasis'' |url=http://www.orchidsnewguinea.com/orchid-information/genus/genuscode/69|publisher=Orchids of New Guinea |accessdate=18 January 2019}}</ref><ref name="China">{{cite web |last1=Chen |first1=Xinqi |last2=Wood |first2=Jeffrey J. |title=''Thelasis'' |url=http://www.efloras.org/florataxon.aspx?flora_id=2&taxon_id=132750 |publisher=Flora of China |accessdate=18 January 2019}}</ref><ref name="ATROK">{{cite web |author1=D.L.Jones |author2=T.Hopley |author3=S.M.Duffy |author1-link=David L. Jones (botanist) |year=2010 |access-date=28 May 2021 |url=http://www.canbr.gov.au/cpbr/cd-keys/RFKOrchids/key/rfkorchids/Media/Html/genera/Thelasis.htm |title=''Thelasis'' |website=Australian Tropical Rainforest Orchids |publisher=Centre for Australian National Biodiversity Research (CANBR), Australian Government}}</ref>
==Taxonomy and naming== The genus ''Thelasis'' was first formally described in 1825 by Carl Ludwig Blume who published the description in ''Bijdragen tot de flora van Nederlandsch Indië ''.<ref name=APNI>{{cite web|title=''Thelasis''|url= https://id.biodiversity.org.au/instance/apni/521039|publisher=APNI|accessdate=18 January 2019}}</ref><ref name="Blume">{{cite book |last1=Blume |first1=Carl Ludwig |title=Bijdragen tot de flora van Nederlandsch Indië (Part 7) |date=1825 |location=Batavia |pages=385–386 |url=https://www.biodiversitylibrary.org/item/9224#page/103/mode/1up |accessdate=18 January 2019}}</ref> The name ''Thelasis'' is derived from the Ancient Greek word ''thelazo'' meaning "suckle" or "nurse",<ref name="RWB">{{cite book|last1=Brown|first1=Roland Wilbur|title=The Composition of Scientific Words|date=1956|publisher=Smithsonian Institution Press|location=Washington, D.C.|page=769}}</ref> possibly referring to a small nipple-like structure on the column.<ref name="ATROK" />
===Species list=== The following is a list of species of ''Thelasis'' accepted by the Plants of the World Online as at October 2025:<ref name="PoWO" /> * ''Thelasis angustifolia'' <small>J.J.Sm.</small> - New Guinea * ''Thelasis bifolia'' <small>Hook.f.</small> - Assam * ''Thelasis borneensis'' <small>Schltr.</small> - Borneo * ''Thelasis capitata'' <small>Blume</small> - conical fly orchid, Christmas Island, Thailand, Malaysia, Indonesia, Philippines * ''Thelasis carinata'' <small>Blume</small> - triangular fly orchid, Queensland, Thailand, Malaysia, Indonesia, Philippines, New Guinea, Solomon Islands, Samoa * ''Thelasis carnosa'' <small>Ames & C.Schweinf. in O.Ames</small> - Sabah * ''Thelasis cebolleta'' <small>J.J.Sm.</small> - Borneo * ''Thelasis celebica'' <small>Schltr.</small> - Sulawesi * ''Thelasis compacta'' <small>Schltr.</small> - New Guinea * ''Thelasis copelandii'' <small>Kraenzl. in H.G.A.Engler</small> - New Guinea * ''Thelasis cycloglossa'' <small>Schltr.</small> - New Guinea * ''Thelasis gautierensis'' <small>J.J.Sm.</small> - New Guinea * ''Thelasis globiceps'' <small>J.J.Sm.</small> - New Guinea * ''Thelasis javanica'' <small>J.J.Sm.</small> - Java * ''Thelasis khasiana'' <small>Hook.f.</small> - Yunnan, Assam, Thailand, Vietnam * ''Thelasis longifolia'' <small>Hook.f.</small> - Nepal, India, Sikkim, Bhutan, Assam * ''Thelasis macrobulbon'' <small>Ridl</small> - Malaysia, Borneo * ''Thelasis mamberamensis'' <small>J.J.Sm.</small> - New Guinea * ''Thelasis micrantha'' <small>(Brongn.) J.J.Sm.</small> - Myanmar, Thailand, Vietnam, Malaysia, Indonesia, Philippines, New Guinea * ''Thelasis obtusa'' <small>Blume</small> - Bali, Java, Borneo, Sumatra, Philippines * ''Thelasis palawensis'' <small>(Schltr.) Ormerod</small> * ''Thelasis perpusilla'' <small>(C.S.P.Parish & Rchb.f.) Schuit.</small> – Indochina * ''Thelasis pygmaea'' <small>(Griff.) Lindl.</small> - Hainan, Hong Kong, Taiwan, Yunnan Nepal, Sikkim, Assam, Bhutan, Andaman & Nicobar Islands, Indochina, Malaysia, Indonesia, New Guinea, Bismarck Islands, Solomon Islands * ''Thelasis rhomboglossa'' <small>(Schltr.) Kraenzl. in H.G.A.Engler</small> - Sumatra * ''Thelasis sphaerocarpa'' <small>(Schltr.) J.J.Sm.</small> * ''Thelasis succosa'' <small>Carr</small> - Malaysia * ''Thelasis variabilis'' <small>Ames & C.Schweinf. in O.Ames</small> - Sabah, Sarawak * ''Thelasis wariana'' <small>(Schltr.) Schuit. & de Vogel</small> - New Guinea
==Distribution== Orchids in the genus ''Thelasis'' are found in China, Taiwan, the Indian subcontinent, the Andaman Islands, Cambodia, Laos, Myanmar, the Nicobar Islands, Thailand, Vietnam, Borneo, Java, the Lesser Sunda Islands, Peninsular Malaysia, the Maluku Islands, the Philippines, Sulawesi, Sumatra, Christmas Island, the Bismarck Archipelago, New Guinea, the Solomon Islands, Queensland (Australia) and Samoa.<ref name="PoWO" />
==See also== * List of Orchidaceae genera
==References== {{Reflist}} *{{Commons-inline|Thelasis|''Thelasis''}}
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Category:Thelasis Category:Podochileae genera