Pterostylis is a terrestrial deciduous genus in the Orchidaceae family of some 100 or so species of orchids found mainly in New Zealand, Australia, Papua New Guinea and New Caledonia. The common name of this tuberous orchid is Greenhood - a number of species have green flowers with the dorsal sepal forming a "hood" over the rest of the flower. The name Pterostylis is based on the Greek words meaning winged column (pteron - a wing, stylis - a column). In a number of species, the flower has a hinged lip that swings backwards when touched by an insect, forming a tube with the column and wings. The trapped insect is then forced to crawl out of the tube, removing the pollen in the process. Jones & Clements (2002, Australian Orchid Research volume 4) proposed segregating from this genus the following genera: Bunochilus, Crangonorchis, Diplodium, Eremorchis, Hymenochilus, Linguella, Oligochaetochilus, Petrorchis, Pharochilum, Plumatichilos, Ranorchis, Speculantha, Stamnorchis, Taurantha, Urochilus. This has not yet been accepted by everyone so it is unclear which name to list the plants under on the wiki. For now we’ll list them both places.
Pterostylis curta R.Br., the blunt greenhood, is a quite common species from south east Australia and Tasmania, where it occurs in shrub and woodland areas. It is an easy subject for frost free potted culture in a well draining medium and has received the RHS Award of Garden Merit. Like most Pterostylis, it requires a dry summer rest. It flowers in mid spring.
The pictures show plants grown by Martin Bohnet as received from European exchange 005, donated by Wim Boens.
Pterostylis longifolia was changed to Pterostylis melagramma by Jones & Clements and is now included in Bunochilus as Bunochilus melagrammus. It grows in moist areas in forests in shade in southeastern Australia. It has narrow pointed leaves clasping the 40 cm. stem and 1 to 7 slightly nodding hooded green flowers which are translucent with darker green markings. The lower sepals are deflexed and the tapered brownish lip has a dark central stripe and bristles. Photos taken by Bob Rutemoeller and Mary Sue Ittner in the Grampians, Victoria, October 2007.
Pterostylis nutans produces a solitary nodding translucent flower to 2.5 cm. long on a 25 cm. stem. It has a basal rosette of wavy-edged stalked leaves. The hairy lip protrudes in the front of the flower. This orchid grows in moist sheltered areas in open forests and woodland in southeastern Queensland and southeastern Australia and on the north island of New Zealand. Photos taken October 2007 in the Grampians by Bob Rutemoeller and Mary Sue Ittner.
Pterostylis tasmanica grows on heathland and heathy forest in well drained soils in New Zealand, New South Wales, Victoria, South Australia and Tasmania. It is similar to Pterostylis plumosa but has smaller flowers and long yellow hairs on the lip. The flower is about 2.5 cm. long with the upper hooded part translucent with a netted pattern of dark green lines. This species has been included in Plumatichilos with other bearded Greenhoods as Plumatichilos tasmanicum syn. Plumatichilos tasmanicus. But this name has not been universally accepted and there is a different spelling in different data bases of the name. Photos taken by Bob Rutemoeller and Mary Sue Ittner October 2007 near Apollo Bay where it was growing in heathland
Pterostylis sp. This unknown species was seen in a forested area in southwestern Western Australia and photographed by Bob Rutemoeller, September 2007. It appears to be in the nana subgroup which has been included by Jones and Clement in Linguella. Malcolm Thomas suspects it may be Linguella dilatata.
Hybrids
Pterostylis 'RK Katano' (nutans x stricta, usually with the alba form of nutans) is a cross created by Heinrich Beyrle and was registered in 2011. It is a very vigorous hybrid multiplying rapidly - easily factor 3-5 per year. Starting growth in September it hibernates as a set of leaves under frost free conditions before sending up flowers by late spring. Like most Pterostylis it needs a dry summer rest. Pictures by Martin Bohnet show how the flower color varies from almost pure white to greenish in different years.
