Aizoaceae

Mesembryanthemum guerichianum seedling IMG 8167-cropped

File:LL-Q14196 (afr)-Oesjaar-vygie.wav

Aptenia cordifolia flower leaves

Carpobrotus specimen with pink flowers

Cheiridopsis denticulata

Aizoaceae, commonly known as the ice plant family, is a diverse and widespread family of flowering plants. The family is notable for its highly succulent species, adapted to arid and semi-arid environments. This adaptation makes them an important group of plants for the study of evolution, ecology, and horticulture. Aizoaceae includes both annual and perennial plants, and is predominantly found in the southern hemisphere, especially in Africa, with a high concentration of species in the Cape Floristic Region of South Africa.

Description

Members of the Aizoaceae family are characterized by their succulent leaves, which are often covered in small, glistening epidermal cells that resemble ice crystals, hence the common name "ice plants." Flowers within the family are typically large, brightly colored, and daisy-like, attracting a variety of pollinators. The fruits are mostly capsules with several seeds, which can vary in their dispersal mechanisms, often adapted to benefit from water for seed dispersal.

Taxonomy

The Aizoaceae family is classified within the order Caryophyllales, and it has been subject to extensive taxonomic revision. The family is divided into several subfamilies and numerous genera. The exact number of species within the family is still under debate, with estimates ranging from 1,800 to over 2,500 species.

Subfamilies and Genera

The family is traditionally divided into four subfamilies:

• Ruschioideae: This subfamily includes many of the well-known succulent genera, such as Lithops (living stones) and Ruschia.
• Mesembryanthemoideae: Known for the genus Mesembryanthemum, which contains many species with striking flowers.
• Aizooideae: Contains the genus Aizoon and a few others, characterized by less succulent leaves.
• Sesuvioideae: Includes the genus Sesuvium, which are often found in coastal areas and have a more widespread distribution.

Distribution and Habitat

Aizoaceae species are predominantly found in the southern hemisphere, with a major center of diversity in the Cape Floristic Region of South Africa. However, their range extends to other parts of Africa, Madagascar, Australia, and the Arabian Peninsula. These plants are well adapted to arid and semi-arid environments, thriving in conditions where water is scarce.

Ecological Role

Plants in the Aizoaceae family play a significant role in their ecosystems. They are important for soil stabilization, especially in arid regions where soil erosion is a concern. Their flowers provide a vital source of nectar for pollinators, including bees, butterflies, and birds. Additionally, the succulent nature of these plants allows them to act as a water source for various animals during dry periods.

Uses

Many species within the Aizoaceae family are cultivated for their ornamental value, appreciated for their unique shapes, textures, and vibrant flowers. Some, like the genus Carpobrotus, are used in landscaping for ground cover, especially in areas prone to drought. Others are grown in gardens and homes as interesting specimens due to their unusual appearance and low water requirements.

Conservation

While many Aizoaceae species are common and widely cultivated, others face threats from habitat loss, overcollection, and climate change. Conservation efforts are important to protect the natural habitats of these plants, especially in biodiversity hotspots like the Cape Floristic Region. In situ and ex situ conservation strategies, including seed banking and cultivation in botanical gardens, are employed to preserve the genetic diversity of this family.