About Diuris littoralis D.L.Jones & C.J.French
Diuris littoralis is a tuberous perennial herb, commonly known as the Green Range donkey orchid. It produces two or three linear leaves, measuring 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 grow on a flowering stem 180–300 mm (7.1–11.8 in) tall; each flower is 25–35 mm (0.98–1.38 in) long and 25–30 mm (0.98–1.18 in) wide. The dorsal sepal of this orchid is egg-shaped, 8–11 mm (0.31–0.43 in) long and 8–13 mm (0.31–0.51 in) wide. Its lateral sepals are narrowly oblong, 12–19 mm (0.47–0.75 in) long, 2–3 mm (0.079–0.118 in) wide, and held either parallel or crossed. The petals are broadly elliptic to nearly so, 12–14 mm (0.47–0.55 in) long and 9–11 mm (0.35–0.43 in) wide, growing on a stalk 3–5 mm (0.12–0.20 in) long. The labellum is 7–9 mm (0.28–0.35 in) long and divided into three lobes. The central lobe is 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 are widely spaced apart, oblong in shape, and measure 7–9 mm (0.28–0.35 in) long and 3–5 mm (0.12–0.20 in) wide. A single smooth yellow callus ridge runs along the midline of the labellum. Flowering occurs from late July to early September. This species grows in coastal and near-coastal shrublands and woodlands. It inhabits well-drained laterite sites, clay areas near streams, and shallow sand overlying limestone. Its distribution spans between Denmark and Esperance, across the Avon Wheatbelt, Esperance Plains, Jarrah Forest and Mallee bioregions of south-western Western Australia.
