Pterostylis cycnocephala, commonly known as the swan greenhood, is a plant in the orchid family Orchidaceae and is endemic to south-eastern Australia. It has a rosette of leaves and up to 24 green flowers which have a labellum with a dark green, beak-like appendage. It is widespread and common from the Darling Downs in Queensland to Tasmania, usually growing with grasses.
Pterostylis cycnocephala, is a terrestrial, perennial, deciduous, herb with an underground tuber. It has a rosette of between six and twelve dark green leaves at the base of the flowering spike, each leaf NaNsigfig=1NaNsigfig=1 long and NaNsigfig=1NaNsigfig=1 wide. Up to 24 shiny green flowers NaNsigfig=1NaNsigfig=1 long and about 4sigfig=1NaNsigfig=1 wide are borne on a flowering spike NaNsigfig=1NaNsigfig=1 tall. Three to six stem leaves are wrapped around the flowering spike. The dorsal sepal and petals form a hood or "galea" over the column. The dorsal sepal is blunt and curved downwards with the sides turned down. The lateral sepals turn downwards, about 6sigfig=1NaNsigfig=1 long and 5sigfig=1NaNsigfig=1 wide, dished and joined for most of their length. The labellum is rectangular in shape, about 2sigfig=1NaNsigfig=1 long and whitish-green with a dark green, beak-like appendage pointing forward at its base. Flowering occurs from August to December.[1] [2] [3] [4]
Pterostylis cycnocephala was first formally described in 1936 by Robert FitzGerald and the description was published in Fitzgerald's book, Australian Orchids.[5] The specific epithet (cycnocephala) is derived from the Ancient Greek words kyknos meaning "swan"[6] and kephale meaning "head", referring to the labellum appendage having the shape of a swan's head and neck.
The swan greenhood is common and widespread from the Darling Downs in Queensland, through New South Wales and Victoria to Tasmania, growing mostly in grassy places.