<p>Phebalium calcicola, a multi-stemmed shrub from south-eastern South Australia, is segregated from the <i>P. squamulosum</i> subsp. <i>squamulosum</i> assemblage and described here as new, based on phenetic distinctness, habitat preference and geographical disjunction. It is compared with <i>P. squamulosum</i> subsp. <i>squamulosum s.str.</i> from the Sydney region, as well as the geographically closest populations from Victoria, which are currently referred as <i>P. squamulosum</i> subsp. <i>squamulosum</i>. A recommendation for the conservation status of this species as Critically Endangered is proposed. An amended key to species of <i>Phebalium</i> in South Australia is provided.</p>