Pterostylis laxa

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 5-25 mm long and 8-16 mm wide. Flowering plants have a single flower 18-25 mm long and 9-12 mm wide which leans slightly forwards on a flowering stem 200-400 mm 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 8-18 mm long. The lateral sepals are erect or backswept, held closely against the galea, have thread-like tips 30-35 mm long and a flat sinus with a central notch between their bases. The labellum is 10-13 mm long, 2-4 mm 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.