obtusus is a plant in the myrtle family, Myrtaceae and is endemic to the south-west of Western Australia.

It is similar to other subspecies of Calothamnus quadrifidus except that its leaves are linear and somewhat rough and scaly and the stamen bundles are relatively short.

obtusus is an erect or straggly shrub which sometimes grows to a height of 3 metres (10 ft) and has a lignotuber.

Flowering mainly occurs from August to October and is followed by fruits which are woody, roughly spherical capsules, 6–10 millimetres (0.2–0.4 in) long.

obtusus is found between Shark Bay, Kalbarri and Mullewa[1] in the Carnarvon, Geraldton Sandplains and Yalgoo biogeographic regions.