Thelymitra basaltica, commonly called the grassland sun orchid, is a species of terrestrial orchid that is endemic to the Australian state of Victoria.
Description
Thelymitra basaltica is a tuberous, perennial herb with a single fleshy but brittle, channelled, dark green, linear to lance-shaped leaf measuring 120–300 mm (5–10 in) in length and 5–15 mm (0.2–0.6 in) in width, with a purplish base. Between two and eight pale blue to pale purplish blue flowers, 15–22 mm (0.6–0.9 in) wide, are crowded along an erect flowering stem 100–300 mm (4–10 in) tall. The sepals and petals are 6–11 mm (0.2–0.4 in) long and 3–7 mm (0.1–0.3 in) wide. The column is pale blue, 4–6.5 mm (0.16–0.26 in) long and 2.5–3.5 mm (0.098–0.14 in) wide. The lobe on the top of the anther is dark purplish to reddish brown with a yellow tip, tubular and gently curved. The side lobes curve upwards and bear toothbrush-like tufts of white hairs. Flowering occurs in September and October, but the flowers open only slowly on warm to hot days. The species is self-pollinating.
Taxonomy and Naming
Thelymitra basaltica was first formally described in 2004 by the botanist Jeff Jeanes, and the description was published in the journal Muelleria based on a specimen collected near Rokewood, Victoria. The specific epithet basaltica refers to the orchid's preference for growing in soils derived from basalt.
Distribution and Habitat
This orchid is endemic to Victoria, Australia, and is known only from a small area near Rokewood. It typically grows in clumps in remnant grassland on soils derived from basalt. The species is considered critically endangered due to its restricted distribution and habitat loss.
Conservation Status
Thelymitra basaltica is listed as critically endangered, as its known range is limited to the volcanic plains of Victoria, an area that has been extensively cleared for agriculture and urban development.
