Overview
Jackson’s Sun Orchid (Thelymitra jacksonii) is a strikingly beautiful and rare terrestrial sun orchid native to the swamp margins and seasonally wet paperbark flats of southern Western Australia. Unlike typical blue-flowered sun orchids, this threatened species boasts breathtaking starry flowers in warm hues of terracotta bronze, reddish-orange, and golden amber. Opening only on warm, sunny spring days, it represents one of the most visually stunning members of the Western Australian flora.
Biology and Physical Characteristics
Thelymitra jacksonii produces a solitary, thick, fleshy, dark green basal leaf that is channelled and up to 20 centimeters long. In late spring (October to December), a robust flowering scape rises up to 50 centimeters, bearing between two and eight brilliantly colored flowers. The perianth segments are broadly lanceolate, opening into flat stars colored vivid reddish-bronze or terracotta with golden margins. The central reproductive column is ornate, featuring a dark blackish-purple hooded mid-lobe crowned with bright yellow cresting teeth and two prominent lateral tufts of golden hairs.
Behavior and Ecology
True to its classification as a sun orchid (genus Thelymitra), Thelymitra jacksonii requires warm temperatures (typically above 20°C) and direct, bright sunlight to trigger its floral petals to expand. On cloudy or cold days, the blossoms remain tightly closed to protect pollen from dampness. The flowers are food-deceptive mimics, attracting native pollen-seeking bees (such as Lasioglossum) with its colorful column tufts that resemble pollen-laden anthers, achieving cross-pollination without producing edible rewards.
Conservation and Human Impact
Thelymitra jacksonii is classified as Endangered under Western Australian conservation status due to its exceptionally small total population size and restricted distribution. The primary hazards include altered hydrological regimes from nearby agricultural drainage, unseasonal wildfires that burn peat substrates, and competition from invasive introduced weeds. Conservation programs focus on GPS population monitoring, seed banking, and working with land managers to protect swamp catchments.
Interesting Factoid
Named in honor of botanist and photographer Greg Jackson, who discovered the species in the Walpole wilderness, this orchid opens its spectacular terracotta blooms only during the sunniest hours of late spring.
Last updated: October 2026