Pterostylis striata explained

Pterostylis striata, commonly known as the mainland striped greenhood, is a species of orchid endemic to south-eastern mainland Australia. As with similar orchids, the flowering plants differ from those which are not flowering. The non-flowering plants have a rosette of leaves but the flowering plants have a single flower with leaves on the flowering spike. This greenhood has a white flower with prominent dark green stripes and a brown-tipped dorsal sepal with a thread-like tip. Mainland striped greenhoods were formerly described as Pterostylis alata but that species is now recognised as a Tasmanian endemic.

Description

Pterostylis striata is a terrestrial, perennial, deciduous, herb with an underground tuber and when not flowering, a rosette of between five and nine dark green, wrinkled leaves, NaNsigfig=1NaNsigfig=1 long and NaNsigfig=1NaNsigfig=1 wide. Flowering plants have a single flower NaNsigfig=1NaNsigfig=1 long and NaNsigfig=1NaNsigfig=1 wide borne on a spike NaNsigfig=1NaNsigfig=1 high with three to five spreading stem leaves. The flowers are white with dark green stripes and a brownish tip. The dorsal sepal and petals are fused, forming a hood or "galea" over the column. The dorsal sepal curves forward with a thread-like tip NaNsigfig=1NaNsigfig=1 long. The lateral sepals are held closely against the galea and have erect, thread-like tips NaNsigfig=1NaNsigfig=1 long and a flat sinus with a small groove between their bases. The labellum is NaNsigfig=1NaNsigfig=1 long, about 3sigfig=1NaNsigfig=1 wide, straight and just visible above the sinus. Flowering occurs from May to August.[1] [2] [3]

Taxonomy and naming

Pterostylis striata was first formally described in 1877 by Robert FitzGerald from a specimen found near Yass. Fitzgerald published the description in his book Australian Orchids.[4] Plants in this species were formerly described as Pterostylis alata but that species is now recognised as a Tasmanian endemic. The State Herbarium of South Australia still lists Pterostylis alata as occurring in that state.[5]

Distribution and habitat

The mainland striped greenhood grows in a range of habitats from tea-tree scrub to forest and is widespread in Victoria. In New South Wales it is found south from Orange.

Notes and References

  1. Book: Jones. David L.. A complete guide to native orchids of Australia including the island territories. 2006. New Holland. Frenchs Forest, N.S.W.. 978-1877069123. 296–297.
  2. Web site: Jeanes. Jeff. Pterostylis striata. Royal Botanic Gardens Victoria: vicflora. 8 June 2017.
  3. Web site: Jones. David L.. Pterostylis striata. Royal Botanic Gardens Sydney: plantnet. 8 June 2017.
  4. Web site: Pterostylis striata. APNI. 8 June 2017.
  5. Web site: Pterostylis alata. State Herbarium of South Australia. 8 June 2017.