Thelymitra silena, commonly called the madonna sun orchid, is a species of orchid that is endemic to Tasmania. It has a single thick, fleshy, channelled leaf and up to fifteen pale blue flowers with an almost spherical yellow lobe on top of the anther.
Thelymitra silena is a tuberous, perennial herb with a single thick, fleshy, channelled, linear to lance-shaped leaf NaNsigfig=1NaNsigfig=1 long and NaNsigfig=2NaNsigfig=2 wide with a purplish base. Between five and fifteen pale blue flowers NaNsigfig=2NaNsigfig=2 wide are arranged on a flowering stem NaNsigfig=1NaNsigfig=1 tall. The sepals and petals are NaNsigfig=1NaNsigfig=1 long and NaNsigfig=1NaNsigfig=1 wide. The column is white to cream-coloured, NaNsigfig=2NaNsigfig=2 long and about 5sigfig=1NaNsigfig=1 wide. The lobe on the top of the anther is light brown and gently curved with a yellow, almost spherical tip but with a deep notch. The side lobes are curved with sparse toothbrush-like tufts of white hairs. Flowering occurs in October and November.[1] [2]
Thelymitra silena was first formally described in 1999 by David Jones from a specimen collected on Clarke Island and the description was published in The Orchadian.[3] The specific epithet (silena) is derived from the Latin word meaning "a bearded, bald, woodland deity, similar to but olderthan a satyr",[4] referring to the column of this orchid.[5]
The madonna sun orchid usually grows in grassy forest and is found near the north and east coasts of Tasmania and on Clarke Island.