Pterostylis aphylla

Pterostylis aphylla, commonly known as the leafless greenhood, is a species of orchid endemic to Tasmania. 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 in this species, the flowering plants have a single green and white flower with a brown tip and lack leaves apart from a few small scales.

Description
Pterostylis aphylla is a terrestrial, perennial, deciduous, herb with an underground tuber. Non-flowering plants have a rosette of dark green leaves 4-10 mm long and 3-8 mm wide. Flowering plants have up to five moderately crowded green and white flowers with a dark brown tip, on a flowering spike, 70-150 mm. The dorsal sepal and petals are fused, forming a hood or "galea" over the column. The dorsal sepal is erect near its base, then curves forward with a short point. The lateral sepals are erect, held closely against the galea with thread-like tips about 3 mm long that do not project above the galea. The sinus between the bases of the lateral sepals curves inward and has a small notch in the centre. The labellum is about 3 mm long, 71 mm wide, dark brown and not visible outside the intact flower. Flowering occurs from October to March.

Taxonomy and naming
Pterostylis aphylla was first formally described in 1840 by John Lindley from a specimen collected in the north-east of Tasmania and the description was published in The Genera and Species of Orchidaceous Plants.

Distribution and habitat
The leafless greenhood is widespread in Tasmania where it grows in forest, heath and buttongrass moorland.