Frithia humilis flowers grow solitary and sessile (stalkless) or nearly so from among the leaves. The calyx base or receptacle is enlarged into a cup-shape around the ovary. The five unequal calyx lobes are leaf-like, forming a tube above the inferior ovary.
The petals are white or pale lilac towards their tips, growing in about two whorls, joined near the base. The flower centre is yellow on petal bases and anthers.
There are three rings of stamens in the flower centre surrounded by one of staminodes (filaments lacking anthers). There are five nectar glands in the flower base in the interest of pollinator enticement. Flower diameter is about 2,5 cm. Flowers open mid-morning, closing mid-afternoon, depending on the weather. Flowering happens in spring and summer.
The fruit has five or six locules similar to those of Delosperma but without valve wings. The capsules break off soon after ripening. They absorb water like sponges or dry out in response to environmental conditions, disintegrating gradually and dispersing seeds as they roll and tumble.
The only other Frithia species, F. pulchra, grows more to the west on the Magaliesberg in Gauteng and North West. It flowers darker purple, the plants slightly bigger (Frandsen, 2017; Leistner, (Ed.), 2000; Smith, et al, 1998; Herre, 1971; iNaturalist; http://pza.sanbi.org).