| 词条 | Pterostylis aenigma |
| 释义 |
| name = Enigmatic greenhood | image = | image_caption = | status_system = EPBC | status = EN | genus = Pterostylis | species = aenigma | authority = D.L.Jones & M.A.Clem.[1] | synonyms_ref = [1] | synonyms = Pterostylis x aenigma D.L.Jones & M.A.Clem. }} Pterostylis aenigma, commonly known as the enigmatic greenhood is a species of orchid endemic to Victoria. It has a rosette of leaves and a single green and white flower which leans forward and has a brownish point on the end. It is a rare orchid, occurring at only one site with fewer than 100 individual plants and is thought to be a natural hybrid between two species that grow nearby. DescriptionPterostylis aenigma has a rosette of between three and eight dark green, fleshy, flat leaves, each leaf {{convert|40-60|mm|in|sigfig=2|abbr=on}} long and {{convert|15-18|mm|in|sigfig=1|abbr=on}} wide. A single green and white flower is borne on a flowering spike {{convert|150-300|mm|in|sigfig=1|abbr=on}} high. The flowers are {{convert|40-45|mm|in|sigfig=2|abbr=on}} long, {{convert|14-18|mm|in|sigfig=1|abbr=on}} wide and lean forward or "nod". The dorsal sepal and petals are joined and curve forward forming a hood over the column. The dorsal sepal is longer than the petals and has a pointed tip. The tip of the hood is brownish. There is a notch in the sinus between the lateral sepals and a large gap between the lateral sepals and petals. The lateral sepals are olive brown and have thread-like tips {{convert|25-35|mm|in|sigfig=2|abbr=on}} long. The labellum protrudes through the sinus and is {{convert|18-21|mm|in|sigfig=1|abbr=on}} long, about {{convert|4|mm|in|sigfig=1|abbr=on}} wide, curved, dark brown and blunt. Flowering occurs between November and December.[1][2][3][4]Taxonomy and namingPterostylis aenigma was first described in 1993 by David Jones and Mark Clements from a specimen collected near Omeo. The description was published in Muelleria.[5] The authors noted that this species is possibly a hybrid between Pterostylis cucullata and P. furcata (later corrected to P. falcata), both of which grow nearby.[6] It is now accepted as Pterostylis x aenigma by some authorities.[7][4] The specific epithet (aenigma) is a Latin word meaning "something obscure, inexplicable, a riddle or mystery"[8] in reference to the puzzling taxonomy and distribution of this orchid.[6] Distribution and habitatThe enigmatic greenhood grows in moist places near streams in open forest at an altitude of {{convert|950|m|ft|sigfig=1|abbr=on}} near Omeo.[1][2][3][4] ConservationAbout 50 plants of Pterostylis aenigma were known in 2003 but only five were located in 2005. The population occurs in the Alpine National Park but is nevertheless threatened by grazing, weed invasion and site disturbance. The species is classified as "Endangered" by the Victorian Government and as "Endangered" (EN) under the Australian Government Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act) and a recovery plan has been prepared.[3][4] References1. ^1 {{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=978-1877069123|page =309}} {{Taxonbar|from=Q15491600}}2. ^1 {{cite web|last1=Jeanes|first1=Jeff|title=Pterostylis x aenigma|url=https://vicflora.rbg.vic.gov.au/flora/taxon/d025fc46-cad0-4542-b327-73d822f88a42|publisher=Royal Botanic Gardens Victoria: vicflora|accessdate=1 May 2017}} 3. ^1 2 {{cite web|title=National recovery plan for the Enigmatic Greenhood (Pterostylis aenigma)|url=http://www.environment.gov.au/system/files/resources/cf12ca26-84d4-4703-8642-3ea4e5de13ee/files/pterostylis-aenigma.pdf|publisher=Australian Government Department of the Environment|accessdate=1 May 2017}} 4. ^1 2 3 {{cite web|title=Action statement: Enigmatic greenhood|url=https://www.environment.vic.gov.au/__data/assets/pdf_file/0008/33002/Enigmatic_Greenhood_Pterostylis_aenigma.pdf|publisher=Victorian Government Department of Sustainability and Environment|accessdate=1 May 2017}} 5. ^{{cite web|title=Pterostylis aenigma|url=https://id.biodiversity.org.au/instance/apni/582519|publisher=APNI|accessdate=1 May 2017}} 6. ^1 {{cite journal|last1=Jones|first1=David L.|last2=Clements|first2=Mark A.|title=New species of Pterostylis R.Br. (Orchidaceae) from Victoria and New South Wales|journal=Muelleria|date=1993|volume=8|issue=1|pages=73–75|url=https://www.rbg.vic.gov.au/documents/Muelleria_8(1),_p73-84,_Jones__Clements,_new_Pterostylis.pdf|accessdate=8 March 2018}} 7. ^1 2 {{cite web|title=Pterostylis x aenigma|url=https://id.biodiversity.org.au/instance/apni/553165|publisher=APNI|accessdate=1 May 2017}} 8. ^{{cite book|last1=Brown|first1=Roland Wilbur|title=The Composition of Scientific Words|date=1956|publisher=Smithsonian Institution Press|location=Washington, D.C.|page = 302}} 4 : Pterostylis|Endemic orchids of Australia|Orchids of Victoria (Australia)|Plants described in 1993 |
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