Diuris amplissima D.L.Jones

Leaves 2 or 3, 100–220 × 2–2.5 mm, folded. Flower stem 400–900 mm tall, 3–8-flowered. Flowers 30–50 mm across, yellowish brown to brown with purplish suffusions and a purple labellum midlobe; petals yellowish brown, dorsal sepal brownish to purple-brown, labellum lateral lobes yellowish brown to purplish, midlobe purple. Dorsal sepal erect, 12–15 × 16–23 mm. Lateral sepals deflexed, 18–28 × 3–4.5 mm. Petals obliquely erect to erect; stalk 5–7 mm long, purple-brown; blade elliptical, 18–30 × 12–15 mm, with a yellowish reverse stripe. Labellum 12–16 mm long; lateral lobes 10–15 × 5–8 mm; midlobe convex, margins downcurved, wedge-shaped when flattened, 10–14 × 10–12 mm, apex recurved. Callus ridge 1, 2–3 mm long.

Localised; forming vegetative colonies in moist, grassy areas in Eucalyptus wandoo woodland and among shrubs in karri forests in freely draining sands.