short-leaved donkey orchid

Diuris brevifolia is a tuberous, perennial herb with between four and eight, often twisted leaves which are 70–120 mm (3–5 in) long and 3–4 mm (0.1–0.2 in) wide. Up to five bright yellow flowers 15–20 mm (0.6–0.8 in) wide are borne on a flowering stem 150–400 mm (6–20 in) tall. There are two brown spots on the base of the dorsal sepal and the labellum callus is outlined in brown. The dorsal sepal is erect or bent upwards, 12–15 mm (0.5–0.6 in) long, 6–7 mm (0.2–0.3 in) wide. The lateral sepals are greenish, linear to lance-shaped, 13–16 mm (0.5–0.6 in) long, 3–4 mm (0.1–0.2 in) wide and turn downwards, more or less parallel to each other. The petals are erect or curved backwards, have a dark brown stalk 4–6 mm (0.16–0.24 in) long with a blade 9–11 mm (0.35–0.43 in) long and 6–7 mm (0.2–0.3 in) wide. The labellum is egg-shaped, 12–15 mm (0.5–0.6 in) long and 7–8 mm (0.28–0.31 in) wide with side lobes 5–6 mm (0.20–0.24 in) long and about 3 mm (0.1 in) wide. There are two parallel ridge-like calli about 6–7 mm (0.2–0.3 in) long near the mid-line of the labellum. Flowering occurs from October to December.

The short-leaved donkey orchid grows in a variety of habitats including heath, forest and woodland but is most common around the edges of swamps and river flats. It only occurs to the south of Adelaide and on Kangaroo Island.