About Corybas undulatus (R.Cunn.) Rupp
Corybas undulatus is a terrestrial, perennial, deciduous herb that produces a single leaf. The leaf measures 10–20 mm (0.4–0.8 in) long and 8–18 mm (0.3–0.7 in) wide, is greyish green on its upper surface, and silvery green or reddish on its lower surface. This species bears a single flower that leans backwards. The flower is translucent grey with purplish red and white markings, measuring 10–13 mm (0.4–0.5 in) long and 9–12 mm (0.4–0.5 in) wide. The dorsal sepal is spatula-shaped to egg-shaped, with the narrower end oriented toward the base, and measures 12–14 mm (0.5–0.6 in) long and 6–8 mm (0.2–0.3 in) wide. The lateral sepals are thread-like, about 3.5 mm (0.1 in) long and 0.5 mm (0.02 in) wide. The petals are similar in shape to the lateral sepals but shorter. The labellum is tube-shaped at its base and remains tube-shaped for roughly half its length, before opening into a broad, heart-shaped flat section that is 9–12 mm (0.4–0.5 in) long and wide. This exposed section of the labellum has a whitish centre and is covered with tiny bristles. The edges of the labellum have tiny teeth, and there is a small tail-like tip on the lower edge. Flowering of Corybas undulatus occurs from May to July. This is an uncommon, often overlooked species that grows in grassy and heathy forest in coastal eastern Australia, ranging from south of Bundaberg in Queensland to Jervis Bay in New South Wales.
