Adenanthos cacomorphus grows as a small lignotuberous shrub up to one metre (3 ft) high.

He published this species based on a type specimen collected by Kenneth Newbey in Fitzgerald River National Park in 1974.

He therefore chose the specific epithet cacomorpha from the Ancient Greek kakos ("ugly"), and morphe ("form").

By this time, the ICBN had issued a ruling that all genera ending in -anthos must be treated as having masculine gender, so A. cacomorpha became A. cacomorphus.

[1][2] It is endemic to southern Western Australia, restricted to the Fitzgerald River National Park and surrounds.