Pterostylis alveata, commonly known as coastal 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. In this species, the non-flowering plants have a rosette of leaves flat on the ground but the flowering plants have a single small, shiny green and white flower with leaves on the flowering spike.
Pterostylis alveata is a terrestrial, perennial, deciduous, herb with an underground tuber and when not flowering, a rosette of dark green leaves, each leaf 10âÂÂ25 mm long and 5âÂÂ15 mm wide. Flowering plants have a single flower 12âÂÂ15 mm long and 7âÂÂ10 mm wide borne on a spike 100âÂÂ200 mm high with between three and five spreading stem leaves. The flowers are shiny green and white. The sepal and petals are fused, forming a hood or "galea" over the column. The dorsal sepal curves forward with a pointed tip. The sepals are held closely against the galea, have a thread-like tip 12âÂÂ15 mm long and a flat, protruding sinus between their bases. The labellum is 8âÂÂ9 mm long, 3 mm wide, dark brown and blunt, just visible above the sinus. Flowering occurs from May to June.
Pterostylis alveata was first formally described in 1939 by John ("Ros") Garnet from a specimen collected on Snake Island. The description was published in The Victorian Naturalist. The specific epithet (alveata) is a Latin word meaning "hollowed out".
Coastal greenhood grows among grasses in moist coastal woodland and scrub between Melbourne in Victoria and Nelson Bay in New South Wales.