The sometimes large, fleshy Mesembryanthemum crystallinum leaves are lettuce-like and usually folded in along their midribs, the margins wavy. Leaves of several sizes are often seen on younger plants. The dark green to dull green blades are sometimes suffused with purple.
The water cells on the lower leaf surfaces are rich in saponins, chemical substances containing toxic glucosides that foam in water, resembling soap. The saponins occurring in various plant species, including soapworts, serve as a deterrent to herbivores (Van Rooyen and Van Rooyen, 2019; Grenier, 2019; Smith, et al, 2017; Smith, et al, 1998; Manning and Goldblatt, 1997; iNaturalist; Wikipedia).