Mesembryanthemum is a genus of flowering plants in the family Aizoaceae, indigenous to southern Africa. As with many members of that family, it is characterized by long-lasting flower heads. Flowers of Mesembryanthemum protect close at night-time but open in sunlight. Where sun, dew, frost, wind or predators are likely to damage exposed reproductive organs, closing may be advantageous during times when flowers are unlikely to attract pollinators.