Species of orchid
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Pterostylis laxa, commonly known as the antelope greenhood, is a species of orchid endemic to south-eastern Australia. As with similar greenhoods, the flowering plants differ from those which are not flowering. The non-flowering plants have a rosette of leaves flat on the ground but the flowering plants have a single flower with leaves on the flowering spike. This greenhood has green and white flowers with darker green or brown markings and a dorsal sepal with a long thread-like tip.
Description.
"Pterostylis laxa" is a terrestrial, perennial, deciduous, herb with an underground tuber and when not flowering, a rosette of 12 to 25 bright green, egg-shaped leaves lying flat on the ground, each leaf long and wide. Flowering plants have a single flower long and wide which leans slightly forwards on a flowering stem high with between three and five stem leaves. The flowers are green and white with darker green or brown markings. The dorsal sepal and petals are fused, forming a hood or "galea" over the column. The dorsal sepal has a thread-like tip long. The lateral sepals are erect or backswept, held closely against the galea, have thread-like tips long and a flat sinus with a central notch between their bases. The labellum is long, wide, dark-coloured, curved, pointed and visible above the sinus. Flowering occurs from January to April.
Taxonomy and naming.
"Pterostylis laxa" was first formally described in 1968 by John Blackmore from a specimen collected in the Upper Grose Valley. The description was published in "The Orchadian". The specific epithet ("laxa") is a Latin word meaning "loose" or "slack".
Distribution and habitat.
The antelope greenhood grows among grasses on slopes in forest in north-eastern Victoria and in eastern New South Wales as far north as the Northern Tablelands.
References.
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