About Thelymitra grandiflora Fitzg.
Thelymitra grandiflora, commonly called the giant sun orchid, is a tuberous perennial herb. It produces a single erect, fleshy, channelled, dark green leaf that is linear to lance-shaped, measuring 250 to 400 mm (10 to 20 in) long and 25 to 35 mm (0.98 to 1.4 in) wide. Up to forty dark metallic to greenish blue flowers with darker veins, each 30 to 40 mm (1 to 2 in) wide, are arranged on a flowering stem 300 to 1,000 mm (10 to 40 in) tall. Its sepals and petals are 15 to 20 mm (0.6 to 0.8 in) long and 6 to 7 mm (0.2 to 0.3 in) wide. The plant's central column is white to cream-coloured, 6 to 7 mm (0.24 to 0.28 in) long and about 5 mm (0.2 in) wide. The lobe on the top of the anther is pale brown with a yellow tip, strongly curved, and has a shallow notch plus irregular teeth. The side lobes have mop-like tufts of white hairs at their ends. The flowers are insect pollinated and only open in warm weather. Flowering occurs from September to December. This orchid grows in forest and scrubland, often in rocky locations. It is widespread and locally common in the Mount Lofty Ranges and Southern Flinders Ranges. It has also been recorded on the Yorke Peninsula and Kangaroo Island, but it is possibly now extinct in those two areas.
