The family Aizoaceae is widely recognised by taxonomists. It once went by the botanical name "Ficoidaceae", now disallowed. The
APG II system of 2003 (unchanged from the
APG system of 1998) also recognizes the family, and assigns it to the order
Caryophyllales in the clade
core eudicots. The APG II system also classes the former families Mesembryanthemaceae Fenzl, Sesuviaceae Horan. and Tetragoniaceae Link under the family Aizoaceae.
The common Afrikaans name "vygie" meaning "small fig" refers to the
fruiting capsule, which resembles the true fig.[3] Glistening epidermal bladder cells give the family its common name "ice plants".[4]
Most species (96%, 1782 species in 132 genera) in this family are endemic to arid or semiarid parts of Southern
Africa in the
Succulent Karoo.[5] Much of the Aizoaceae's diversity is found in the Greater
Cape Floristic Region, which is the most plant-diverse temperate region in the world.[6] A few species are found in
Australia and the
Central Pacific area.[7]
Most fig-marigolds are
herbaceous, rarely somewhat woody, with
sympodial growth and
stems either erect or prostrate.
Leaves are simple, opposite or alternate, and more or less succulent with entire (or rarely toothed) margins.
Flowers are perfect in most species (but unisexual in some), actinomorphic, and appear singularly or in few-flowered cymes developing from the leaf axils.
Sepals are typically five (3–8) and more or less connate (fused) below. True
petals are absent. However, some species have numerous linear petals derived from staminodes.[8] The seed capsules have one to numerous seeds per cell and are often
hygrochastic, dispersing seeds by "jet action" when wet.[4]
Evolution
The radiation of the Aizoaceae, specifically the subfamily Ruschioideae, was one of the most recent among the
angiosperms, occurring 1.13–6.49 Mya. It is also one of the fastest radiations ever described in the angiosperms, with a diversification rate of about 4.4 species per million years.[9] This diversification was roughly contemporaneous with major radiations in two other succulent lineages,
Cactaceae and Agave.[10]
C. edulis was
introduced to California in the early 1900s to stabilize soil along railroad tracks and has become invasive.[22] In southern California, ice plants are sometimes used as firewalls;[23] however, they do burn if not carefully maintained.[24]