Pterostylis stricta

Northern greenhood
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Clade:	Angiosperms
Clade:	Monocots
Order:	Asparagales
Family:	Orchidaceae
Subfamily:	Orchidoideae
Tribe:	Cranichideae
Genus:	Pterostylis
Species:	P. stricta
Binomial name
Pterostylis stricta Clemesha & B.Gray

Pterostylis stricta, commonly known as the northern greenhood, is a species of orchid endemic to Queensland. It has a rosette of leaves and when flowering a single translucent white flower with green lines, a reddish-brown tip and a curved, protruding labellum.

Description

Pterostylis stricta is a terrestrial, perennial, deciduous, herb with an underground tuber and a rosette of wrinkled leaves. Each leaf is 15–60 mm (0.6–2 in) long and 10–20 mm (0.4–0.8 in) wide. When flowering, there is a single white flower with green lines and a reddish-brown tip, 20–25 mm (0.8–1 in) long and 10–12 mm (0.4–0.5 in) wide which is borne on a flowering spike 100–300 mm (4–10 in) high. The dorsal sepal and petals are fused to form a hood or "galea" over the column, the dorsal sepal about the same length as the petals, all with a sharp point. There is a wide gap at each side of the flower between the petals and lateral sepals. The lateral sepals are erect with a tapering tip 12–15 mm (0.5–0.6 in) long and there is a broad, bulging sinus between them. The labellum is 14–16 mm (0.55–0.63 in) long, about 4 mm (0.2 in) wide, dark reddish-brown and curved, protruding above the sinus. Flowering occurs from March to July.

Taxonomy and naming

Pterostylis stricta was first described in 1972 by Stephen Clemesha and Bruce Gray and the description was published in The Orchadian from a specimen collected near Ravenshoe. The specific epithet (stricta) is a Latin word meaning "draw together", "hold in check" or "bind".

Distribution and habitat

The northern greenhood grows with grasses and in sheltered gullies in forest between Mount Finnigan and Paluma at altitudes of between 800 and 1,250 m (2,600 and 4,100 ft).