It is a terrestrial herb with a single, heart-shaped leaf and up to five translucent greenish-white flowers with pinkish markings and is found growing in forests on the north coast of the state.

Acianthus exiguus is a terrestrial, perennial, deciduous, sympodial herb with a single heart-shaped, glabrous, dark green leaf which is light reddish-purple on its lower surface.

The thick, fleshy callus covering most of the central area is green and has many small pimple-like papillae on the outer half.

[3][4] Acianthus exiguus was first formally described by David Jones in 1991 and the description was published in Australian Orchid Research from specimens found near Wardell.

[3][7] In a 1995 paper published in the journal Allertonia, Paul Kores claimed that A. exiguus and 3 other species are not distinct from A. fornicatus and should be regarded as a synonyms.