Green Range Donkey Orchid

Diuris littoralis is a tuberous, perennial herb with two or three linear leaves 80–200 mm (3.1–7.9 in) long and 3–8 mm (0.12–0.31 in) wide. Up to six yellow flowers with brown and mauve markings, 25–35 mm (0.98–1.38 in) long and 25–30 mm (0.98–1.18 in) wide are borne on a flowering stem 180–300 mm (7.1–11.8 in) tall. The dorsal sepal is egg-shaped, 8–11 mm (0.31–0.43 in) long and 8–13 mm (0.31–0.51 in) wide, the lateral sepals narrowly oblong, parallel or crossed, 12–19 mm (0.47–0.75 in) long and 2–3 mm (0.079–0.118 in) wide. The petals are more or less broadly elliptic, 12–14 mm (0.47–0.55 in) long and 9–11 mm (0.35–0.43 in) wide on a stalk 3–5 mm (0.12–0.20 in) long. The labellum is 7–9 mm (0.28–0.35 in) long with three lobes - the centre lobe wedge-shaped with down-curved edges, 6–8 mm (0.24–0.31 in) long and 4–7 mm (0.16–0.28 in) wide, the side lobes spread widely apart and oblong, 7–9 mm (0.28–0.35 in) long and 3–5 mm (0.12–0.20 in) wide. There is a single smooth, yellow callus ridge along the mid-line of the labellum. Flowering occurs from late July to early September.

Green Range donkey orchid grows in coastal and near-coastal shrublands and woodlands on well-drained laterite, in clay near streams and in shallow sand over limestone between Denmark and Esperance in the Avon Wheatbelt, Esperance Plains, Jarrah Forest and Mallee bioregions of south-western Western Australia.