Thelymitra aggericola, commonly called the bleak sun orchid, is a species of orchid that is endemic to Tasmania. It has a single long, curved leaf and up to seven or more white to pale blue flowers, green on their back side.
Thelymitra aggericola is a tuberous, perennial herb with a single curved, linear to lance-shaped leaf NaNsigfig=1NaNsigfig=1 long, NaNsigfig=1NaNsigfig=1 wide and often as long as, or longer than the flowering stem. Up to seven or more white to pale blue flowers NaNsigfig=1NaNsigfig=1 wide are arranged on a flowering stem NaNsigfig=1NaNsigfig=1 tall. The sepals and petals are NaNsigfig=1NaNsigfig=1 long, NaNsigfig=1NaNsigfig=1 wide and green on the reverse side. The column is white, NaNsigfig=2NaNsigfig=2 long and about 2.5sigfig=1NaNsigfig=1 wide. The lobe on the top of the anther is pale yellow to light brown, sharply curved with an inflated hood. The side lobes have dense, mop-like tufts of white hairs. Flowering occurs in October and November.[1] [2]
Thelymitra aggericola was first formally described in 1999 by David Jones from a specimen collected near Temma south of Arthur River and the description was published in The Orchadian.[3] The specific epithet (aggericola) is derived from the Latin agger meaning "heap" or "mound"[4] and -cola meaning "dweller".
The bleak sun orchid usually grows in rock crevices and shallow soil pockets close to the coast in the north-west and south-east of Tasmania. The plants open freely on warm to hot days and many seed capsules are produced, suggesting that the flowers are capable of self pollination.