Thelymitra orientalis is a rare species of orchid in the family Orchidaceae and is endemic to southern continental Australia. It has a single thread-like, cylindrical leaf and a single deep blue, streaked flower. It is similar to T. mucida but is distinguished from that species by its filiform leaf and smaller flower.
Thelymitra orientalis is a tuberous, perennial herb with a single thread-like, cylindrical leaf about 50sigfig=1NaNsigfig=1 long and 2sigfig=1NaNsigfig=1 wide with a red base. A single deep blue flower with 6 to 8 darker streaks, up to 10sigfig=1NaNsigfig=1 wide is borne on a flowering stem up to 100sigfig=1NaNsigfig=1 tall. The sepals and petals are NaNsigfig=1NaNsigfig=1 long and NaNsigfig=2NaNsigfig=2 wide. The column is a rich purple colour, NaNsigfig=2NaNsigfig=2 long and about 2sigfig=1NaNsigfig=1 wide. The lobe on the top of the anther is black with a yellow tip divided into two parts with wavy edges. The side lobes have a few yellow hairs. Flowering occurs between late October and early-November and the flowers only open on hot days.[1] [2]
Thelymitra orientalis was first formally described in 2010 by Robert Bates from a specimen he collected in The Marshes Native Forest Reserve near Millicent in 2003. The description was published in the Journal of the Adelaide Botanic Garden.[3] The specific epithet (orientalis) is a Latin word meaning "of the east",[4] referring to fact that this orchid is related to T. mucida which is mainly a Western Australian species.
This thelymitra grows in damp heath in high rainfall areas. It is found in western Victoria and the far south-east of South Australia.