Pterostylis

Greenhood
Pterostylis coccina
Scientific classification
Kingdom: Plantae
(unranked): Angiosperms
(unranked): Monocots
Order: Asparagales
Family: Orchidaceae
Subfamily: Orchidoideae
Tribe: Diurideae
Subtribe: Pterostylidinae
Genus: Pterostylis
R.Br., 1810
Type species
Pterostylis curta
R.Br., 1810[1]
Synonyms[2]
  • Diplodium Sw.
  • Oligochaetochilus Szlach.
  • Plumatichilos Szlach.
  • Bunochilus D.L.Jones & M.A.Clem.
  • Crangonorchis D.L.Jones & M.A.Clem.
  • Eremorchis D.L.Jones & M.A.Clem.
  • Hymenochilus D.L.Jones & M.A.Clem.
  • Linguella D.L.Jones & M.A.Clem.
  • Petrorchis D.L.Jones & M.A.Clem.
  • Pharochilum D.L.Jones & M.A.Clem.
  • Ranorchis D.L.Jones & M.A.Clem.
  • Speculantha D.L.Jones & M.A.Clem.
  • Stamnorchis D.L.Jones & M.A.Clem.
  • Taurantha D.L.Jones & M.A.Clem.
  • Urochilus D.L.Jones & M.A.Clem.
Pterostylis coccina, sepals and petals removed
(1) - Lip
(2) - Hinge
(3) - stigma
(4) - pollinia

Pterostylis is a genus of about 120 species of plants in the orchid family, Orchidaceae. Commonly called greenhood orchids, they are terrestrial, deciduous, perennial, tuberous, herbs found in Australia, New Zealand, New Guinea, New Caledonia and one Indonesian island. The flowers are mostly green, sometimes with brown, reddish or white stripes and are distinguished from other orchids by their unusual flower structures and pollination mechanism.

Description

Greenhood orchids are all terrestrial herbs with an underground tuber like many other genera of orchids but are distinguished by a hood-like "galea" formed by the fusing of the dorsal sepal and two lateral petals. The galea curves forward, covers the sexual parts of the flower, is important in the pollination process and is about as long as the lateral sepals. The dorsal sepal is translucent white with green, reddish or brown stripes. The two lateral sepals are joined at their base, form the front of the flower and usually protrude to form "points" or "ears" which extend above or to the side of the galea. The third (medial) petal forms the highly modified labellum. As in other orchids, the sexual parts of the flower form part of the column and in all greenhoods, this structure has a pair of mostly translucent wings and is also important in pollination.[3][4][5]

The tuber of a greenhood is usually more or less spherical in shape and lasts for about a year then dies. A new one is produced early in the life of the parent tuber at the same time as a new shoot is produced and continues to grow, reaching maturity at the end of the growing season. In some species, a larger number of "daughter" tubers grow, and a colony of orchids is produced. The leaves are either attached in a rosette to the base of the peduncle or "stalk" of the plant by a short petiole, or further up it, in which case the leaves are sessile. There may be one or several flowers on the peduncle.[3][4][5][6]

Most greenhoods are pollinated by insects, nearly always by tiny flies from the family Mycetophilidae or by mosquitoes (Family Culicidae). The insect approaches the flower from downwind, as if attracted by a scent and usually lands on the galea. (In the case of Pterostylis sanguinea, the pollinator is a male fungus gnat of the genus Mycomya which attempts to copulate with the labellum, which produces the chemical attractant.)[7] The insect then enters the flower and either because it has passed a balance point, or because it has touched a sensitive part of the labellum, the labellum moves forward trapping the insect between the column wings, the labellum and other flower parts. Observation of the insect's reaction to entrapment is difficult to observe, but in its struggle to escape, it either deposits pollinia from a previously visited flower or contacts the sticky viscidium and pollinia are attached, then carried to another flower. The features of an actively-moving labellum, along with the galea, are unique to these orchids.[3][6]

The fruit of a greenhood is a dehiscent capsule containing up to 500 tiny seeds and is oblong to elliptic in shape with three ridges. Other parts of the flower wither soon after pollination and the dry remains are attached to the end of the capsule.[3][5]

Taxonomy and naming

The first observation of Pterostylis by European botanists was probably by Joseph Banks when HMS Endeavour visited Botany Bay in 1770 but any specimens collected were lost later in the voyage. The first formal description of a greenhood was by Jacques Labillardière who collected a specimen from Bruny Island and gave it the name Disperis alata.[8] After several name changes, Disperis alata is now known as Pterostylis alata. John White, the first surgeon-general of the colony of New South Wales collected several species and George Caley collected 208 greenhood specimens from 16 species and described them in great detail, including details of their habitat and gave them names like Druids Cap patersoni but did not publish his work.[3]

The genus Pterostylis was first raised by Robert Brown who formally described 19 species but did not nominate a type species. The species he described were collected from the east coast of the mainland and from Tasmania and the descriptions were published in Prodromus Florae Novae Hollandiae.[1][3][9]

Alan Cunningham was the first to describe a New Zealand species, P. banksii and John Lindley described the first four Western Australian species, P. vittata, P. pyramidalis, P. barbata and P. scabra from specimens collected by James Drummond.[3][10] About 120 species have now been described and about 100 of them are endemic to Australia.[4]

David Jones and Mark Clements have proposed the separating of some species of Pterostylis into the genera Bunochilus, Crangonorchis, Diplodium, Eremorchis, Hymenochilus, Linguella, Oligochaetochilus, Petrorchis, Pharochilum, Plumatichilos, Ranorchis, Speculantha, Stamnorchis, Taurantha and Urochilus[11] but the change has not been adopted by Australian herbaria.[4]

The genus name (Pterostylis) is derived from the Ancient Greek words pteron meaning "wing" and stylos meaning "a pillar"[12] referring to the "wings" on the column.[6]

Distribution and habitat

Orchids in the genus Pterostylis occur mostly in Australia but are also found in New Zealand, including some of its smaller islands such as Chatham Island, and in New Caledonia, New Guinea, New Britain, New Ireland and on Seram Island in Indonesia. In Australia they are found in all states and Lord Howe Island, but not in the Northern Territory. They grow in a wide range of habitats, especially in temperate zones and are found in grassland, heath, scrub, woodland and forest, including rainforest. They sometimes grow in semi-arid areas but usually near rocks or crevices where there is run-off during rain. In tropical regions they tend to grow at higher altitudes where temperatures are lower. Most have periods of dormancy which coincide with climatic extremes, surviving as small tubers until favourable conditions return.[3]

Species

  • Pterostylis abrupta D.L.Jones – tablelands greenhood
  • Pterostylis aciculiformis (Nicholls) M.A.Clem. & D.L.Jones
  • Pterostylis acuminata R.Br. – sharp greenhood, pointed greenhood
  • Pterostylis aenigma D.L.Jones & M.A.Clem.
  • Pterostylis aestiva D.L.Jones
  • Pterostylis agathicola D.L.Jones, Molloy & M.A.Clem.
  • Pterostylis agrestis (D.L.Jones) G.N.Backh.
  • Pterostylis alata (Labill.) Rchb.f. – striped greenhood
  • Pterostylis allantoidea R.S.Rogers – shy greenhood
  • Pterostylis alobula (Hatch) L.B.Moore
  • Pterostylis alpina R.S.Rogers – mountain greenhood
  • Pterostylis alveata Garnet
  • Pterostylis anaclasta (D.L.Jones) Janes & Duretto
  • Pterostylis anatona D.L.Jones
  • Pterostylis aneba D.L.Jones
  • Pterostylis angusta A.S.George – narrow-hooded shell orchid, narrow shell orchid
  • Pterostylis aphylla Lindl. – leafless greenhood
  • Pterostylis aquilonia D.L.Jones & B.Gray
  • Pterostylis arenicola M.A.Clem. & J.Stewart
  • Pterostylis areolata Petrie
  • Pterostylis arfakensis (J.J.Sm.) D.L.Jones & M.A.Clem.
  • Pterostylis aspera D.L.Jones & M.A.Clem. – brown-veined shell orchid
  • Pterostylis atrans D.L.Jones – blunt-tongue green-hood, dark-tip greenhood
  • Pterostylis atriola D.L.Jones – Snug greenhood
  • Pterostylis auriculata Colenso
  • Pterostylis australis Hook.f.
  • Pterostylis banksii A.Cunn.
  • Pterostylis baptistii Fitzg. – king greenhood
  • Pterostylis barbata Lindl. – bird orchid
  • Pterostylis barringtonensis (D.L.Jones) G.N.Backh.
  • Pterostylis basaltica D.L.Jones & M.A.Clem.
  • Pterostylis bicolor M.A.Clem. & D.L.Jones
  • Pterostylis bicornis D.L.Jones & M.A.Clem. – horned greenhood
  • Pterostylis biseta Blackmore & Clemesha – rufa greenhood, rusty hood, veined greenhood
  • Pterostylis boormanii Rupp – sikhs whiskers, Boorman's greenhood
  • Pterostylis brumalis L.B.Moore
  • Pterostylis bryophila D.L.Jones
  • Pterostylis bureaviana Schltr.
  • Pterostylis calceolus M.A.Clem.
  • Pterostylis cardiostigma D.Cooper
  • Pterostylis caulescens L.O.Williams
  • Pterostylis cernua D.L.Jones, Molloy & M.A.Clem.
  • Pterostylis chaetophora M.A.Clem. & D.L.Jones
  • Pterostylis cheraphila D.L.Jones & M.A.Clem.
  • Pterostylis chlorogramma D.L.Jones & M.A.Clem.
  • Pterostylis chocolatina (D.L.Jones) G.N.Backh.
  • Pterostylis ciliata M.A.Clem. & D.L.Jones – hairy rufous greenhood
  • Pterostylis clavigera Fitzg.
  • Pterostylis clivicola (D.L.Jones) G.N.Backh.
  • Pterostylis cobarensis M.A.Clem.
  • Pterostylis coccina Fitzg. – scarlet greenhood
  • Pterostylis collina (Rupp) M.A.Clem. & D.L.Jones
  • Pterostylis commutata D.L.Jones – midland greenhood
  • Pterostylis concava D.L.Jones & M.A.Clem. – cupped banded greenhood
  • Pterostylis concinna R.Br. – trim greenhood
  • Pterostylis conferta (D.L.Jones) G.N.Backh.
  • Pterostylis crassa (D.L.Jones) G.N.Backh.
  • Pterostylis crassicaulis (D.L.Jones & M.A.Clem.) G.N.Backh.
  • Pterostylis crassichila D.L.Jones
  • Pterostylis cucullata R.Br. –leafy greenhood
  • Pterostylis curta R.Br. –blunt greenhood
  • Pterostylis cycnocephala Fitzg. –swan greenhood
  • Pterostylis daintreeana F.Muell. ex Benth.
  • Pterostylis decurva R.S.Rogers – summer greenhood
  • Pterostylis depauperata F.M.Bailey
  • Pterostylis despectans (Nicholls) M.A.Clem. & D.L.Jones
  • Pterostylis dilatata A.S.George – tall snail orchid, robust snail orchid
  • Pterostylis diminuta (D.L.Jones) G.N.Backh.
  • Pterostylis dolichochila D.L.Jones & M.A.Clem. – long-tongued shell orchid
  • Pterostylis dubia R.Br. – large-leaf greenhood, blue-tongued greenhood
  • Pterostylis elegans D.L.Jones
  • Pterostylis erecta T.E.Hunt - erect maroonhood
  • Pterostylis erythroconcha M.A.Clem. & D.L.Jones – red shell orchid
  • Pterostylis exalla (D.L.Jones) G.N.Backh.
  • Pterostylis excelsa M.A.Clem.
  • Pterostylis extranea (D.L.Jones) Janes & Duretto
  • Pterostylis ferruginea (D.L.Jones) G.N.Backh.
  • Pterostylis fischii Nicholls
  • Pterostylis flavovirens (D.L.Jones) R.J.Bates
  • Pterostylis foliata Hook.f. – slender greenhood
  • Pterostylis frenchii (D.L.Jones) A.P.Br. – tuart rufous greenhood
  • Pterostylis furcata Lindl. – forked greenhood, sickle greenhood
  • Pterostylis gibbosa R.Br. – Illawarra greenhood
  • Pterostylis glyphida (D.L.Jones) G.N.Backh.
  • Pterostylis graminea Hook.f.
  • Pterostylis grandiflora R.Br. – superb greenhood, cobra greenhood
  • Pterostylis hamata Blackmore & Clemesha
  • Pterostylis hamiltonii Nicholls – red-veined shell orchid
  • Pterostylis hians D.L.Jones – opera house orchid
  • Pterostylis hildae Nicholls – rainforest greenhood
  • Pterostylis hispidula Fitzg.
  • Pterostylis humilis R.S.Rogers
  • Pterostylis incognita (D.L.Jones) G.N.Backh.
  • Pterostylis insectifera M.A.Clem. – insect-lipped rufous greenhood
  • Pterostylis irsoniana Hatch
  • Pterostylis irwinii D.L.Jones
  • Pterostylis jonesii G.N.Backh.
  • Pterostylis laxa Blackmore – antelope greenhood
  • Pterostylis lepida (D.L.Jones) G.N.Backh.
  • Pterostylis leptochila M.A.Clem. & D.L.Jones – Ravensthorpe rufous greenhood
  • Pterostylis lineata (D.L.Jones) G.N.Backh.
  • Pterostylis lingua M.A.Clem.
  • Pterostylis littoralis (D.L.Jones) R.J.Bates
  • Pterostylis loganii (D.L.Jones) G.N.Backh.
  • Pterostylis longicurva Rupp – long-tongued greenhood
  • Pterostylis longifolia R.Br. – tall greenhood
  • Pterostylis longipetala Rupp – small autumn-greenhood, curved greenhood
  • Pterostylis lustra D.L.Jones
  • Pterostylis macilenta (D.L.Jones) G.N.Backh.
  • Pterostylis macrocalymma M.A.Clem. & D.L.Jones – large-headed rufous greenhood
  • Pterostylis macrosepala (D.L.Jones) G.N.Backh.
  • Pterostylis major (D.L.Jones) G.N.Backh.
  • Pterostylis maxima M.A.Clem. & D.L.Jones
  • Pterostylis melagramma D.L.Jones
  • Pterostylis metcalfei D.L.Jones – Ebor greenhood
  • Pterostylis micromega Hook.f.
  • Pterostylis mirabilis (D.L.Jones) R.J.Bates
  • Pterostylis mitchellii Lindl. in T.L.Mitchell
  • Pterostylis montana Hatch
  • Pterostylis monticola D.L.Jones – mountain greenhood, large mountain greenhood
  • Pterostylis multiflora (D.L.Jones) G.N.Backh.
  • Pterostylis mutica R.Br. – midget greenhood, blunt greenhood
  • Pterostylis mystacina (D.L.Jones) Janes & Duretto
  • Pterostylis nana R.Br. – dwarf greenhood, snail greenhood
  • Pterostylis nigricans D.L.Jones & M.A.Clem.
  • Pterostylis nutans R.Br. – parrot's beak orchid, nodding greenhood
  • Pterostylis oblonga D.L.Jones
  • Pterostylis obtusa R.Br. – blunt greenhood, blunt-tongue greenhood
  • Pterostylis oliveri Petrie
  • Pterostylis ophioglossa R.Br. – snake's tongue greenhood
  • Pterostylis ovata M.A.Clem. – Gawler Range greenhood
  • Pterostylis paludosa D.L.Jones, Molloy & M.A.Clem.
  • Pterostylis papuana Rolfe
  • Pterostylis parca (D.L.Jones) G.N.Backh.
  • Pterostylis parviflora R.Br. - baby greenhood, tiny greenhood
  • Pterostylis patens Colenso
  • Pterostylis pearsonii (D.L.Jones) Janes & Duretto
  • Pterostylis pedina (D.L.Jones) Janes & Duretto
  • Pterostylis pedoglossa Fitzg. – tailed greenhood, prawn greenhood
  • Pterostylis pedunculata R.Br. – little red riding-hood, maroon hood
  • Pterostylis petrosa D.L.Jones & M.A.Clem.
  • Pterostylis picta M.A.Clem. – painted rufous greenhood
  • Pterostylis planulata D.L.Jones & M.A.Clem.
  • Pterostylis plumosa Cady - bird orchid, bearded orchid
  • Pterostylis porrecta D.L.Jones, Molloy & M.A.Clem.
  • Pterostylis praetermissa M.A.Clem. & D.L.Jones
  • Pterostylis prasina (D.L.Jones) G.N.Backh.
  • Pterostylis pratensis D.L.Jones – Liawenee greenhood
  • Pterostylis procera D.L.Jones & M.A.Clem.
  • Pterostylis psammophila (D.L.Jones) R.J.Bates
  • Pterostylis puberula Hook.f.
  • Pterostylis pulchella Messmer
  • Pterostylis pusilla R.S.Rogers – ruddy hood, ruddyhood
  • Pterostylis pyramidalis Lindl. - tall snail orchid, leafy snail orchid
  • Pterostylis recurva Benth. – recurved shell orchid, jug orchid
  • Pterostylis reflexa R.Br. – dainty greenhood, small autumn greenhood
  • Pterostylis revoluta R.Br. – autumn greenhood
  • Pterostylis riparia D.L.Jones
  • Pterostylis robusta R.S.Rogers – sharp-leaf greenhood, larger striped-greenhood
  • Pterostylis roensis M.A.Clem. & D.L.Jones – rufous greenhood
  • Pterostylis rogersii E.Coleman – curled-tongue shell orchid
  • Pterostylis rubenachii D.L.Jones – Arthur River greenhood
  • Pterostylis rubescens (D.L.Jones) G.N.Backh.
  • Pterostylis rufa R.Br. - rufous greenhood, ruddy hood, rusty hood
  • Pterostylis russellii T.E.Hunt
  • Pterostylis sanguinea D.L.Jones & M.A.Clem. – dark banded greenhood
  • Pterostylis sargentii C.R.P.Andrews – frog greenhood
  • Pterostylis saxicola D.L.Jones & M.A.Clem.
  • Pterostylis scabra Lindl. – bronze shell orchid, green-veined shell orchid
  • Pterostylis scabrida Lindl. – rough greenhood
  • Pterostylis scoliosa D.L.Jones
  • Pterostylis setifera M.A.Clem.
  • Pterostylis silvicultrix (F.Muell.) D.L.Jones & M.A.Clem.
  • Pterostylis sinuata (D.L.Jones) Janes & Duretto – Northampton midget greenhoood, western swan greenhood
  • Pterostylis smaragdyna D.L.Jones & M.A.Clem.
  • Pterostylis spathulata M.A.Clem. – spoon-lipped rufous greenhood
  • Pterostylis spissa (D.L.Jones) G.N.Backh.
  • Pterostylis splendens D.L.Jones & M.A.Clem.
  • Pterostylis squamata R.Br. – ruddy greenhood
  • Pterostylis stenochila D.L.Jones – green-lip greenhood
  • Pterostylis stenosepala (D.L.Jones) G.N.Backh.
  • Pterostylis stricta Clemesha & B.Gray
  • Pterostylis subtilis D.L.Jones
  • Pterostylis tanypoda D.L.Jones, Molloy & M.A.Clem.
  • Pterostylis tasmanica D.L.Jones – small bearded greenhood
  • Pterostylis taurus M.A.Clem. & D.L.Jones
  • Pterostylis tenuicauda Kraenzl.
  • Pterostylis tenuis (D.L.Jones) G.N.Backh. – swamp greenhood
  • Pterostylis tenuissima Nicholls – swamp greenhood
  • Pterostylis thulia (D.L.Jones) Janes & Duretto
  • Pterostylis timorensis Schuit. & J.J.Verm.
  • Pterostylis timothyi (D.L.Jones) Janes & Duretto – fawn snail orchid
  • Pterostylis torquata D.L.Jones
  • Pterostylis tristis Colenso
  • Pterostylis trullifolia Hook.f.
  • Pterostylis truncata Fitzg. – little dumpy, brittle greenhood, little dumpies
  • Pterostylis tunstallii D.L.Jones & M.A.Clem. – Tunstall's greenhood
  • Pterostylis turfosa Endl. in J.G.C.Lehmann – bearded bird orchid
  • Pterostylis uliginosa D.L.Jones – marsh greenhood
  • Pterostylis umbrina (D.L.Jones) G.N.Backh.
  • Pterostylis venosa Colenso
  • Pterostylis ventricosa (D.L.Jones) G.N.Backh.
  • Pterostylis vernalis (D.L.Jones) G.N.Backh.
  • Pterostylis viriosa (D.L.Jones) R.J.Bates
  • Pterostylis vitrea (D.L.Jones) Bostock
  • Pterostylis vittata Lindl. – banded greenhood, baggy britches
  • Pterostylis wapstrarum D.L.Jones – fleshy greenhood
  • Pterostylis williamsonii D.L.Jones – brown-lip greenhood
  • Pterostylis woollsii Fitzg. – long-tailed greenhood
  • Pterostylis xerophila M.A.Clem.
  • Pterostylis ziegeleri D.L.Jones – Cape Portland greenhood

Hybrid greenhoods

References

  1. 1 2 "Pterostylis R.Br.". APNI. Retrieved 6 June 2016.
  2. ↑ Kew World Checklist of Selected Plant Families
  3. 1 2 3 4 5 6 7 8 Jones, David L.; Clements, Mark A. (2002). "A Reassessment of Pterostylis R.Br. (Orchidaceae)". Australian Orchid Research. 4: 3–63.
  4. 1 2 3 4 "Genus Pterostylis". Royal Botanic Gardens Sydney; plantnet. Retrieved 6 June 2016.
  5. 1 2 3 "Pterostylis". FloraBase. Western Australian Government Department of Parks and Wildlife.
  6. 1 2 3 "Pterostylis". trin; Lucid keys. Retrieved 6 June 2016.
  7. ↑ Phillips, Ryan D.; Scaccabarozzi, Daniella; Retter, Bryony A.; Hayes, Christine; Brown, Graham R.; Dixon, Kingsley W.; Peakall, Rod (22 December 2013). "Caught in the act: pollination of sexually deceptive trap-flowers by fungus gnats in Pterostylis (Orchidaceae)". Annals of Botany. 113 (4): 629–641. doi:10.1093/aob/mct295.
  8. ↑ "Disperis alata". APNI. Retrieved 6 June 2016.
  9. ↑ Brown, Robert (1810). Prodromus Florae Novae Holliandiae (Volume 1). London. pp. 326–328. Retrieved 6 June 2016.
  10. ↑ Lindley, John (1840). A Sketch of the Vegetation of the Swan River Colony (appendix). Piccadilly, London: James Ridgway. p. 53.
  11. ↑ Jones, David L.; Clements, Mark A. (2002). "A New Classification of Pterostylis R.Br. (Orchidaceae)". Australian Orchid Research. 4: 64–124.
  12. ↑ Moore (ed.), Bruce (2002). The Australian Oxford Dictionary (1999 ed.). South Melbourne, Vic.: Oxford University Press. p. 1087. ISBN 0195507932.

Other sources

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