The simple, sessile leaves of Leucospermum muirii are spiralling or alternate on the stems. The leaves are wedge-shaped to linear, the lateral margin parts entire. The blades are a pale grey-green and velvety from soft, short, pale hairs.
The leaf-tips are about as broad as the flat to incurving blades, ending in three to seven pinkish red, cartilaginous teeth. These swollen teeth are extra-floral nectaries, glandular bodies that secrete a sugary liquid.
Such extra-floral nectaries exist in more than 2000 plant species belonging to more than 64 families. They may be positioned on leaves as in Leucospermum, but also on petioles, rachises, bracts, stipules, pedicels, fruit and more. The nectaries vary in size, shape and the nature of their secretions, used by insects such as ants and ladybirds beetles (Bean and Johns, 2005; www.plantzafrica.com; https://edis.ifas.ufl.edu).