by Steve Purnell
Fig marigold or Icicle plant is a name for any of several South African taxa of Mesembryanthemum which are cultivated as ornamental plants for their showy pink or white flowers. "Pebble plant" or "Ice plant" are other but rather ambiguous common names, usually referring to other Aizoaceae.
Mesembryanthemum is a member of the family Aizoaceae; like many members of this 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.
Ornamental Mesembryanthemum may escape into the wild and consequently has become widely naturalized outside their native range. They are considered an invasive weed in certain places. Some species are hallucinogenic plants and as such may be subject to legal restrictions (e.g. Louisiana State Act 159).
(Courtesy of Wikipedia)