The labellum is tube shaped at its base and for about half its length before opening into a broad heart-shaped dish 9–12 mm (0.4–0.5 in) long and wide.

This part of the labellum has a whitish centre and is covered with tiny bristles.

[2][3] The tailed helmet orchid was first formally described in 1833 by Richard Cunningham, who gave it the name Corysanthes undulata and published the description in the New South Wales Magazine.

[5] The specific epithet (undulatus) is a Latin word meaning "wavy".

[6] Corybas undulatus is an uncommon, often overlook species growing in grassy and heathy forest in coastal areas of Queensland south from Bundaberg to Jervis Bay in New South Wales.