Carpobrotus edulis is a creeping plant with succulent leaves in the genus Carpobrotus, native to South Africa. Its common names include hottentot-fig, sour fig, ice plant, highway ice plant, or vygie.
Carpobrotus edulis is a creeping, mat-forming succulent species. It grows year round, with individual shoot segments growing more than 1 m (3 ft) per year.[citation needed] It can grow to at least 50 m (165 ft) in diameter. The leaves are a dull-green or yellow-green colour that may fade to pink with age. They are very slightly curved and have serrated sides near the tips.
The yellow flowers are produced from April to October, and range from 6.4 to 15.2 centimetres (2+1⁄2 to 6 inches) in diameter. Two of the calyx lobes are longer, extending further than the petals. The flowers open in the morning in bright sunlight and close at night. The receptacle is somewhat wedge-shaped, tapering down to the pedicel. The fruit is multi-chambered, ripening from green to yellow.
The sour fig grows on coastal and inland slopes in South Africa from Namaqualand in the Northern Cape through the Western Cape to the Eastern Cape. It is often seen as a pioneer on disturbed sites.
Carpobrotus edulis has naturalised in many other regions throughout the world, and is an invasive species in several parts, notably Australia, California and the Mediterranean, all of which have similar climates. The species has escaped from cultivation and has become invasive, posing a serious ecological problem by forming vast monospecific zones, lowering biodiversity, and competing directly with several threatened or endangered plant species for nutrients, water, light, and space.
The success of C. edulis as an invader is linked to its stoloniferous growth habit and clonal integration, traits commonly associated with invasive species. Physiological integration between ramets increases survival, biomass accumulation and clonal spread especially where competing with native species. The species often exhibits greater phenotypic plasticity than many native species, enabling it to establish and expand into under contrasting conditions including shaded coastal cliffs and nutrient-enriched sites. Such plasticity has raised concerns about its continual spread, especially in the face of changing climatic conditions.
Through hybridization, invasive C. edulis can gain genetic diversity and novel traits that further enhance its adaptability. The species readily engages in genetic exchanges with other Carpobrotus, such as C. chilensis, leading to hybrid variants with unique genetic combinations that allow them to thrive and outcompete native flora. Analysis of chloroplast DNA has revealed a large amount of genetic similarities between C. edulis and C. chilensis, indicating that the two may share a common ancestor.
