Thelymitra aristata

Thelymitra aristata, commonly called the great sun orchid, is a species of orchid that is endemic to south-eastern Australia. It has a single large, thick leaf and bracts and up to forty crowded blue or purplish flowers with darker veins.

Description
Thelymitra aristata is a tuberous, perennial herb with a single thick, fleshy, channelled, linear to lance-shaped leaf 250-400 mm long and 25-40 mm wide. Between six and forty pale blue, deep blue or purple flowers with darker veins 30-40 mm wide are crowded on a flowering stem 300-1000 mm tall. There are between three and five large bracts along the flowering stem. The sepals and petals are 15-20 mm long and 6-7 mm wide. The column is cream-coloured to white or pale blue, 6-7 mm long and 5-5.5 mm wide. The lobe on the top of the anther is purplish brown with a finely-toothed yellow tip. The side lobes have dense, mop-like tufts of white hairs. The flowers are scented, insect-pollinated and open on sunny days. Flowering occurs from September to January.

Taxonomy and naming
Thelymitra aristata was first formally described in 1840 by John Lindley from a specimen collected in Tasmania and the description was published in his book The genera and species of Orchidaceous plants. The specific epithet (aristata) is a Latin word meaning "with ears".

Distribution and habitat
The great sun orchid grows in a wide range of habitats from swamp margins to open forest. It is found in New South Wales in coastal and near-coastal areas south of Fitzroy Falls, in the southern half of Victoria, in south-eastern South Australia and in Tasmania including King and Flinders Islands.