The genus name Mesembryanthemum is derived from the Greek word mesembria, meaning ‘midday’, and anthemom, meaning ‘flower’, referring to the flowers of this group that typically open at midday (noon). Mesembryanthemum cordifolium was known as Aptenia cordifolia until 2007 when the genus Aptenia was reduced to synonymy under Mesembryanthemum. The former genus name, Aptenia, is derived from the Greek word, apten, meaning ‘wingless’, and refers to the wingless seeds. The species name, cordifolium, is derived from the in Latin words, cordi, meaning ‘heart’, and folium, meaning ‘leaf’, referring to the heart-shaped leaves.

This species is endemic to South Africa but is now grown all over the world. The genus Aptenia consisted of four species, all now placed in Mesembryanthemum and all occur in the summer rainfall regions of South Africa:
Mesembryanthemum geniculiflorum is an erect deciduous perennial with 4-angled branches,  white to pale yellow flowers and occurs on dry flats in scrambling bush in Namibia, Northern Cape and Eastern Cape.
Mesembryanthemum haeckelianum is a succulent perennial with 4-angled branches that grows flat on to the ground, with flat leaves and pale yellowflowers. It occurs in karroid flats in the Eastern Cape, from Port Elizabeth to Alexandria.
Mesembryanthemum lancifolium is a perennial succulent, 300 mm high. It bears magenta flowers with narrow, lance-shaped leaves and occurs in Limpopo.