Mairia crenata is a dwarf perennial herb growing a basal leaf rosette. Its flowers are presented about 15 cm above the ground.

The spreading, dark to yellow-green leaves are elliptic and leathery. Leaf surfaces are hairy when young, hairless and shiny on top when mature, white-woolly below. The midrib is prominent below; some lateral veins are also visible, angling out and upwards. Leaf margins are scalloped or toothed and slightly rolled under.

These plants are found on stony sandstone slopes and rock ledges from the Cape Peninsula to Uitenhage along the coastal region; also in the Little Karoo. The species is not considered to be threatened in its habitat early in the twenty first century (Vlok and Schutte-Vlok, 2010; Manning, 2009; http://redlist.sanbi.org).