Birds mouth orchid

Orthoceras strictum is a terrestrial, perennial, deciduous, herb with an underground tuber and a tuft of between two and five linear to thread-like, grass-like leaves, 150–300 mm (6–10 in) long and 2–3 mm (0.08–0.1 in) wide. Up to nine flowers 8–10 mm (0.3–0.4 in) wide are borne on a rigid flowering stem 300–600 mm (10–20 in) tall. Flower colour varies from blackish, brownish, maroon to yellowish green. The dorsal sepal is egg-shaped and forms a hood over the rest of the flower, 9–12 mm (0.4–0.5 in) long and 8–10 mm (0.3–0.4 in) wide. The lateral sepals are linear, horn-like, 20–25 mm (0.8–1 in) long, about 1 mm (0.04 in) wide and erect, spreading or curved. The petals are oblong, 8–10 mm (0.3–0.4 in) long, about 3 mm (0.1 in) wide and hidden inside the dorsal sepal. The labellum is 6–10 mm (0.2–0.4 in) long and has three lobes. The middle lobe is elliptic to egg-shaped, 6–7 mm (0.2–0.3 in) long, 5–6 mm (0.20–0.24 in) wide and the side lobes are 5–6 mm (0.20–0.24 in) long, about 1.5 mm (0.06 in) wide. There is a pyramid-shaped callus near the base of the labellum. Flowering occurs from November to February.

The bird's-mouth orchid is widespread but uncommon and occurs in New South Wales, Queensland, South Australia, Tasmania, Victoria and New Caledonia. It grows in a wide range of habitats from grassy forest to heath. The differences between this species and Orthoceras novae-zeelandiae from New Zealand are "very slight and dubious".