Diuris tricolor Fitzg.

Scientific Classification and Growth Form

Diuris tricolor (long-tailed donkey orchid), described by Fitzg., is a tuberous, perennial herb.

Leaf Characteristics

It grows up to three linear leaves that are 200–300 mm (8–10 in) long, 3–4 mm (0.1–0.2 in) wide, and folded lengthwise.

Inflorescence and Flower Basics

Between two and six orange to yellow flowers with white and purplish tints are borne on a 200–400 mm (8–20 in) tall flowering stem, and each flower is 25–30 mm (0.98–1.2 in) wide.

Dorsal Sepal Morphology

The upward-curving dorsal sepal is 10–15 mm (0.4–0.6 in) long, 6–9 mm (0.2–0.4 in) wide, and broadly egg-shaped.

Lateral Sepal Morphology

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.

Petal Morphology

The petals are more or less erect or turned backwards, and are egg-shaped to elliptic; the petal blade is 10–16 mm (0.4–0.6 in) long and 6–10 mm (0.2–0.4 in) wide, borne on a reddish purple stalk 3–7 mm (0.1–0.3 in) long.

Labellum Structure

The labellum is 8–12 mm (0.3–0.5 in) long and has three lobes.

Labellum Central Lobe

The centre lobe is egg-shaped, 6–9 mm (0.2–0.4 in) long and wide, with a central ridge.

Labellum Side Lobes

The side lobes are 3–4.5 mm (0.1–0.2 in) long and about 2 mm (0.08 in) wide.

Labellum Callus Ridges

Two callus ridges about 4 mm (0.2 in) long are located near the mid-line of the labellum.

Flowering Period

Flowering occurs from September to November.

Primary Habitat and Distribution

Long-tailed donkey orchid grows in grassland and forest in south-east Queensland, and grows sporadically south from Deepwater in New South Wales, and in the Australian Capital Territory.

Victoria Distribution Record

A single specimen has been recorded in Victoria, just south of the New South Wales border.