Diuris systena D.L.Jones & L.M.Copel.

Leaves 2 or 3, 150–350 × 3–5 mm, straight. Flower stem 150–350 mm tall, 1–4-flowered. Flowers semi-nodding, 30–35 mm across, lemon yellow, often with dark streaks on dorsal sepal and labellum, lateral sepals brownish green. Dorsal sepal obliquely erect, 9–15 × 4–6 mm. Lateral sepals obliquely deflexed, 18–25 × 2–3.5 mm, parallel. Petals held horizontally, widely divergent; stalk 3–6 mm long, blackish; blade narrowly ovate-lanceolate, 8–18 × 4–6.5 mm. Labellum obliquely decurved, 12–17 mm long; lateral lobes 2–4.5 mm long, deeply and irregularly toothed, papillate; midlobe ovate to ovate-lanceolate, 8–15 × 7–12 mm, pointed. Callus ridges 2, 4–6 mm long, usually dark yellow, densely papillate-hairy, a central ridge developed on base of midlobe.

Uncommon to rare; growing among shrubs or trees mostly around margins of swamps in moist, peaty loam derived from basalt or granite; less commonly in drier habitats.