Pterostylis

Nodding greenhoods Pterostylis nutans, copyright Eric Hunt.

Belongs within: Orchidoideae.

Pterostylis, the greenhood orchids, is an Australasian genus of terrestrial orchids in which the dorsal sepal is curved forwards to form a distinctive hood over the flower.

Characters (from Moore & Edgar 1970): Plant terrestrial, usually glabrous; tubers ovoid to globose, produced close to or at some distance from parent plant. Leaves several, rosette-forming or distributed up flowering stem, almost orbicular to linear. Flowers solitary or more rarely a few-flowered raceme; floral bract often not differentiated. Perianth glabrous or minutely scabrid, mostly green; dorsal sepal uppermost, deeply concave and curved, lateral margins dovetailed into petals to form with them a hood or galea; lateral sepals connate for part or most of their length, free lobes diverging widely or narrowly, tips short or long, acuminate to almost filiform; petals falcate with anterior margins shortly adnate to base of lateral sepals, posterior margins free under dorsal sepal, outer surface with median longitudinal groove into which slightly involucrate margin of dorsal sepal locks. Labellum smallest of the perianth segments, usually included for most of its length, mobile on a claw attached to column-foot; lamina usually undivided, sometimes with hairs but usually without calli, produced, at line of junction with claw, into an appendage that is usually strap-shaped and more or less laciniate at free end. Column elongate, its foot more or less adnate to base of dorsal sepal, bearing on either side of rostellum a more or less quadrangular, partly twisted wing; anther terminal, pollinia two per cell, crescentic, soft but coherent; stigma of two lobes, usually vertically elongated and occupying middle of column; rostellum immediately below anther and high above stigma with which it is connected by a narrow groove.

<==Pterostylis Br. 1810 (nom. cons.)ME70
    |--+--P. cucullataH49
    |  `--P. humilis Rogers 1922H49
    |--P. sect. CatochilusC06
    |    |--P. barbata Lindl. 1839H49 [incl. P. squamataC06, P. turfosa Endl. in Lehm. 1846ME70]
    |    `--+--P. cycnocephala Fitz. 1876H49, ME70
    |       `--P. mutica Brown 1810H49 [incl. P. tristis Colenso 1885ME70]
    |--+--P. alpinaH49
    |  |--P. falcataH49
    |  `--P. furcata Ldl. 1840 [=P. f. var. typica Hatch 1949]H49
    `--P. sect. AntennaeaC06
         |  i. s.: P. micromega Hooker 1853C06, ME70 (see below for synonymy)
         |--+--P. nana Brown 1810 [incl. P. puberula Hooker 1853]H49
         |  `--P. pyramidalisH49
         |--+--P. obtusaH49
         |  |--P. trullifolia Hooker 1853H49 (see below for synonymy)
         |  `--P. venosa Colenso 1896H49 [incl. P. confertifolia Allan 1926ME70, P. trifolia Col. 1899ME70]
         `--+--P. nutans Brown 1810 [incl. P. matthewsii Cheeseman 1915]H49
            `--+--+--P. australis Hooker 1853H49
               |  `--P. montana Hatch 1949H49 (see below for synonymy)
               |--+--+--P. areolata Petrie 1918H49
               |  |  `--P. oliveri Petrie 1894H49
               |  `--+--P. banksii Cunningham 1832H49, ME70 (see below for synonymy)
               |     `--P. graminea Hooker 1853H49
               |          |--P. g. var. gramineaME70
               |          `--P. g. var. rubricaulis Matthews ex Cheeseman 1925 (see below for synonymy)ME70
               `--+--P. bureauvianaH49
                  |--P. foliata Hooker 1853 [incl. P. gracilis Nich. 1927 non P. trullifolia var. gracilis Cheeseman 1915]H49
                  `--+--P. hildaeH49
                     `--P. neocaledonicaH49
Pterostylis incertae sedis:
  *P. curtaME70
  P. acuminataH86
  P. alobula (Hatch) Moore 1969 [=P. trullifolia var. alobula Hatch 1949]ME70
  P. asperaG04
  P. brumalis Moore 1969ME70
  P. celansH49
  P. clavigeraH86
  P. concinnaH86
  P. cryptaH49
  P. gibbosaH86
  P. grandifloraH08
  P. irsoniana Hatch 1950ME70
  P. longifoliaH86
  P. mitchelliH86
  P. parviflora [incl. P. aphylla]H86
  P. pedunculataH87
  P. plumosa Cady 1969ME70
  P. recurvaOS04
  P. reflexaH86
  P. rufaH86
  P. sanguineaGK00
  P. striataH86
  P. vittataGK00
  P. woollsiiH86
Nomen nudum: Pterostylis collina Colenso 1845C45

Pterostylis banksii Cunningham 1832H49, ME70 [=P. banksii var. typica Hatch 1949H49; incl. P. auriculata Colenso 1890ME70, P. emarginata Colenso 1883H49, P. patens Colenso 1886ME70, P. banksii var. patens (Colenso) Hatch 1945ME70, P. speciosa Colenso 1890H49, P. subsimilis Colenso 1896H49]

Pterostylis micromega Hooker 1853C06, ME70 [=P. furcata var. micromega (Hooker) Hatch 1953ME70; incl. P. polyphylla Colenso 1890ME70]

Pterostylis graminea var. rubricaulis Matthews ex Cheeseman 1925 [=Pterostylis montana var. rubricaulis (Cheeseman) Hatch 1949]ME70

Pterostylis montana Hatch 1949H49 [=P. montana var. typica Hatch 1949H49; incl. P. furcata var. linearis Hatch 1949ME70]

Pterostylis trullifolia Hooker 1853H49 [incl. P. trullifolia var. gracilis Cheeseman 1915ME70, P. rubella Colenso 1886ME70, P. trullifolia var. rubella (Colenso) Hatch 1949ME70]

*Type species of generic name indicated

References

[C06] Cheeseman, T. F. 1906. Manual of the New Zealand Flora. John Mackay, Government Printer: Wellington.

[C45] Colenso, W. 1845. Memoranda of an excursion, made in the Northern Island of New Zealand, in the summer of 1841–2; intended as a contribution towards the natural productions of the New Zealand groupe: with particular reference to their botany (concluded). Tasmanian Journal of Natural Science 2: 241–308.

[G04] Gibson, N. 2004. Flora and vegetation of the Eastern Goldfields Ranges: part 7. Middle and South Ironcap, Digger Rock and Hatter Hill. Journal of the Royal Society of Western Australia 87 (2): 49–62.

[GK00] Gibson, N., & G. J. Keighery. 2000. Flora and vegetation of the Byenup-Muir reserve system, south-west Western Australia. CALMScience 3 (3): 323–402.

[H08] Hamilton, A. A. 1908 Notes and exhibits. Proceedings of the Linnean Society of New South Wales 33: 435.

[H86] Hamilton, A. G. 1886. List of the Orchideae of the Mudgee district. Proceedings of the Linnean Society of New South Wales, series 2, 1 (3): 865–878.

[H49] Hatch, E. D. 1949. The New Zealand forms of Pterostylis R. Br. Transactions and Proceedings of the Royal Society of New Zealand 77 (2): 234–246.

[H87] Haviland, E. 1887. Flowering seasons of Australian plants. No. II. Proceedings of the Linnean Society of New South Wales, series 2, 1 (4): 1103–1104.

[ME70] Moore, L. B., & E. Edgar. 1970. Flora of New Zealand vol. 2. Indigenous Tracheophyta: Monocotyledones except Gramineae. A. R. Shearer, Government Printer: Wellington (New Zealand).

[OS04] Obbens, F. J., & L. W. Sage. 2004. Vegetation and flora of a diverse upland remnant of the Western Australian wheatbelt (Nature Reserve A21064). Journal of the Royal Society of Western Australia 87 (1): 19–28.

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