long-tailed donkey orchid

Diuris tricolor is a tuberous, perennial herb with up to three linear leaves 200–300 mm (8–10 in) long, 3–4 mm (0.1–0.2 in) wide and folded lengthwise. Between two and six orange-coloured to yellow flowers with white and purplish tints, 25–30 mm (0.98–1.2 in) wide are borne on a flowering stem 200–400 mm (8–20 in) tall. The dorsal sepal curves upwards, 10–15 mm (0.4–0.6 in) long, 6–9 mm (0.2–0.4 in) wide and broadly egg-shaped. The lateral sepals are narrow linear, 20–65 mm (0.8–3 in) long, much less than 1 mm (0.04 in) wide and turned downwards. The petals are more or less erect or turned backwards, egg-shaped to elliptic, the blade 10–16 mm (0.4–0.6 in) long and 6–10 mm (0.2–0.4 in) wide on a reddish purple stalk 3–7 mm (0.1–0.3 in) long. The labellum is 8–12 mm (0.3–0.5 in) long and has three lobes. The centre lobe is egg-shaped, 6–9 mm (0.2–0.4 in) long and wide with a central ridge. The side lobes are 3–4.5 mm (0.1–0.2 in) long and about 2 mm (0.08 in) wide. There are two callus ridges about 4 mm (0.2 in) long near the mid-line of the labellum. Flowering occurs from September to November.

Long-tailed donkey orchid grows in grassland and forest in south-east Queensland, sporadically south from Deepwater in New South Wales, and in the Australian Capital Territory. A single specimen has been recorded in Victoria, just south of the border.