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 their gametes from night-time dews or frosts but open in sunlight. There is an obvious evolutionary advantage to doing this; 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.
Many Mesembryanthemum species are known as ice plants because of the glistening globular bladder cells covering their stems, fruit and leaves, "... they sparkle like ice crystals". In South Africa, Mesembryanthemums are known as "vygies" (from Afrikaans "vy"), although that term refers to many plants in the family Aizoaceae.
