Thelymitra alcockiae, commonly called Kath's sun orchid, is a species of orchid that is endemic to southern continental Australia. It has a single long, narrow leaf and up to twelve pale blue to deep purplish blue flowers, mauve or reddish on their back side.
Thelymitra alcockiae is a tuberous, perennial herb with a single fleshy, channelled, linear to lance-shaped leaf NaNsigfig=1NaNsigfig=1 long, NaNsigfig=1NaNsigfig=1 wide. Between two and twelve pale blue to deep purplish blue, rarely white 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 mauve or reddish on the reverse side. The column is pale blue or pinkish, NaNsigfig=2NaNsigfig=2 long and about 2sigfig=1NaNsigfig=1 wide. The lobe on the top of the anther is brown with a yellow tip, tubular and sharply curved with an inflated tip. The side lobes have dense, mop-like tufts of white hairs. Flowering occurs from August to October.[1] [2] [3]
Thelymitra alcockiae was first formally described in 2013 by Jeff Jeanes after an unpublished description by David Jones. The formal description was published in Muelleria from a specimen collected near Naracoorte.[4] The specific epithet (alcockiae) honours "Kath Alcock (1925-), botanical artist and field naturalist".
Kath's sun orchid usually grows in drier habitats including shrubland, open forest and woodland. It is locally common in the north-west of Victoria and in South Australia.