Pterostylis melagramma

Pterostylis melagramma, commonly known as the black-stripe leafy greenhood is a plant in the orchid family Orchidaceae and is endemic to south-eastern Australia. Individual plants have either a rosette of three to six leaves or a flowering spike with up to twenty flowers and five to seven stem leaves. The flowers are translucent green with faint darker green lines and have a brownish-yellow labellum with a dark stripe.

Black-striped leafy greenhood
Pterostylis melagramma growing in southern Tasmania
Scientific classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Monocots
Order: Asparagales
Family: Orchidaceae
Subfamily: Orchidoideae
Tribe: Cranichideae
Genus: Pterostylis
Species:
P. melagramma
Binomial name
Pterostylis melagramma
Synonyms[1]
  • Oligochaetochilus melagrammus (D.L.Jones) Szlach.
  • Bunochilus melagrammus (D.L.Jones) D.L.Jones & M.A.Clem.

Description

Pterostylis melagramma, is a terrestrial, perennial, deciduous, herb with an underground tuber. Non-flowering plants have a rosette of between three and six narrow egg-shaped leaves, each leaf 13–50 mm (0.5–2 in) long and 4–11 mm (0.2–0.4 in) wide on a stalk 30–100 mm (1–4 in) high. Flowering plants have up to twenty translucent flowers with faint darker lines on a flowering spike 150–800 mm (6–30 in) high. The flowering spike has between five and seven stem leaves which are 25–80 mm (1–3 in) long and 5–10 mm (0.2–0.4 in) wide. The flowers are 13–15 mm (0.5–0.6 in) long, 4–8 mm (0.2–0.3 in) wide. The dorsal sepal and petals are joined to form a hood over the column with the dorsal sepal suddenly curving downwards near its tip which is often brown. The lateral sepals turn downwards and are 11–13 mm (0.4–0.5 in) long, 6–7 mm (0.2–0.3 in) wide and joined to each other for about half their length. The labellum is about 5 mm (0.2 in) long, 2 mm (0.08 in) wide, brownish-yellow and hairy with a dark stripe along its mid-line. Flowering occurs from June to November.[2][3][4]

Taxonomy and naming

Pterostylis melagramma was first formally described in 1998 by David Jones and the description was published in Australian Orchid Research.[5][3] The specific epithet (melagramma) is derived from the Greek words melas, melanos meaning 'dark' or 'black' and gramme, 'line', referring to the dark stripe on the labellum.[3]

Distribution and habitat

The black-stripe leafy greenhood is widely distributed and common in higher rainfall areas of Victoria and Tasmania and also occurs in south-eastern South Australia and southern New South Wales.[2][3][4][6]

Conservation

This greenhood is classed as "endangered" in South Australia.[6]

References
  1. "Pterostylis melagramma". World Checklist of Selected Plant Families (WCSP). Royal Botanic Gardens, Kew.
  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. 316–317. ISBN 978-1877069123.
  3. Jones, David L. (1998). "Contributions to Tasmanian Orchidology". Australian Orchid Research. 3: 145–146.
  4. Jeanes, Jeff. "Pterostylis melagramma". Royal Botanic Gardens Melbourne: vicflora. Retrieved 7 June 2017.
  5. "Pterostylis melagramma". APNI. Retrieved 7 June 2017.
  6. "Census of South Australian Plants - Orchidaceae". State Herbarium of South Australia: eflora SA. Retrieved 7 June 2017.
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