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.
Pterostylis aphylla is a terrestrial, perennial, deciduous, herb with an underground tuber. Non-flowering plants have a rosette of dark green leaves NaNsigfig=1NaNsigfig=1 long and NaNsigfig=1NaNsigfig=1 wide. Flowering plants have up to five moderately crowded green and white flowers with a dark brown tip, on a flowering spike, NaNsigfig=1NaNsigfig=1. 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 3sigfig=1NaNsigfig=1 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 3sigfig=1NaNsigfig=1 long, 71sigfig=1NaNsigfig=1 wide, dark brown and not visible outside the intact flower. Flowering occurs from October to March.[1]
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.[2] [3]
The leafless greenhood is widespread in Tasmania where it grows in forest, heath and buttongrass moorland.[4]