Pterostylis striata

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.

Mainland striped greenhood
Pterostylis striata growing in the Brisbane Ranges National Park
Scientific classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Monocots
Order: Asparagales
Family: Orchidaceae
Subfamily: Orchidoideae
Tribe: Cranichideae
Genus: Pterostylis
Species:
P. striata
Binomial name
Pterostylis striata

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, 4–15 mm (0.2–0.6 in) long and 3–9 mm (0.1–0.4 in) wide. Flowering plants have a single flower 16–19 mm (0.6–0.7 in) long and 7–9 mm (0.3–0.4 in) wide borne on a spike 40–250 mm (2–10 in) 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 2–4 mm (0.08–0.2 in) long. The lateral sepals are held closely against the galea and have erect, thread-like tips 14–20 mm (0.6–0.8 in) long and a flat sinus with a small groove between their bases. The labellum is 7–9 mm (0.3–0.4 in) long, about 3 mm (0.1 in) wide, straight and just visible above the sinus. Flowering occurs from May to August.[2][3][4]

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.[1] Plants in this species were formerly described as Pterostylis alata but that species is now recognised as a Tasmanian endemic.[4] 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.[2][3][4]

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