(Corpuscularia lehmannii, Manuel M Ramos)
Introduction
South Africa is the global center for Mesembryanthemaceae (the mesembs/ice plants). In a tight mosaic of winter- and summer-rainfall zones, these leaf-succulent shrubs and miniatures pack water into thick leaves, use CAM photosynthesis to save moisture at night, and time growth to brief, reliable pulses of rain.
The Details
Mesembs track geology closely—sandstone, shale, quartzites, and limestone each host characteristic species. On exposed ridges, many stay tiny and compact with windowed or translucent leaf tips that admit light while limiting surface area. In shallow soils and rock cracks, cushion and mat forms reduce wind stress and conserve humidity at the leaf surface.
Flowering follows the rains. In winter-rainfall regions (western Cape and Karoo margins), many species bloom from late winter into spring; farther inland and east, summer thunderstorms drive growth and flower waves. Daisylike blossoms open in bright light, often at midday, to match the activity of small bees, flies, and beetles. Colors range from white and yellow to magenta and orange, sometimes with contrasting centers that guide visitors.
Seed capsules are a signature feature. Hygrochastic fruits remain closed when dry, then open in rain to splash-disperse seeds into nearby crevices and gravel pockets. This rain-triggered release puts seeds exactly where short-lived moisture lingers. Fine seeds germinate best under nurse shrubs or among stones where shade, litter, and cooler surfaces extend the wet period.
In cultivation, sharp drainage, bright light, and seasonal watering are essential. Water during the local “on” season (winter for winter-rainfall mesembs; summer for summer-rainfall kinds) and keep nearly dry in the “off” season. A gritty mix and wide, shallow pots suit fibrous roots and help prevent rot. Field or garden observations benefit from noting rock type, slope, and nurse plants—simple clues that explain why a mesemb thrives in one spot and not a few meters away.
Additional Reading: Mesembryanthemaceae
