Pterostylis
Terrestrial herbs arising from rounded, underground tubers. Leaves radical or cauline; radical leaves in a rosette encircling the base of the scape or borne on a separate plant or stem, stem leaves either well-developed and spreading or reduced and closely sheathing the peduncle. Flowers solitary or up to 15 in a raceme, white translucent or transparent with green or reddish suffusions and markings; petals and sepals united into a galea (hood); dorsal sepal erect, incurved over the column, inflated at the base, apex entire or with a filiform extension; petals curved, well-developed anteriorly, with proximal and/or distal flanges; lateral sepals erect or decurved, connate at the base, tapered into free points. Labellum on a movable claw, undivided or 3-lobed, glabrous or bearing hairs, with or without a basal appendage; callus reduced to a central ridge. Column erect, incurved, with 2 prominent apical wings forming a tunnel between the stigma and anther.
About 250 species, mostly endemic in Australia but also occurring in New Guinea, Ceram, New Caledonia and New Zealand; about 82 species and 3 named hybrids in Victoria.
Measurements of the flowers are taken in a straight line from the base of the galea to the apex of the dorsal sepal.
Up to 16 genera have been recognised within what is here treated as a broadly defined Pterostylis. For further information see e.g. Jones and Clements (2002a, 2002b) and Janes et al.(2010).
Jones, D.L. (1994). Pterostylis. In: Walsh, N.G.; Entwisle, T.J., Flora of Victoria Vol. 2, Ferns and Allied Plants, Conifers and Monocotyledons, pp. 798–830. Inkata Press, Melbourne.
SpinningJanes, J.K. Steane, D.A., Vaillancourt, R.E., Duretto, M.F. (2010). A molecular phylogeny of the subtribe Pterostylidinae (Orchidaceae): resolving the taxonomic confusion. Australian Systematic Botany 23(4 ): 248–259.
Jones, D.L.; Clements, M.A. (2002a). A reassessment of Pterostylis R.Br. (Orchidaceae). . *Australian Orchid Review * 4: 3–63.
Jones, D.L.; Clements, M.A. (2002b). A new classification of Pterostylis R.Br. (Orchidaceae). Australian Orchid Review ** 4**: 64–124.
