Succulent flora of Saudi Arabia

Agavaceae contains only 2 genera, namely Dracaena and Sansevieria. The former (Dracaena ombet) is found in the high altitude areas while the latter, represented by two species (S. ehrenbergii and Sansevieria forskaliana) is usually seen in low lying areas. Members of Agavaceae are of considerable economic importance in the Arab World because of their fibrous leaves/stems which were widely used in making mats, baskets, hats, etc.  All three species have a scattered distribution in the south western region. Cactaceae, a New World family, is represented in Saudi Arabia by two exotic species, Opuntia dellenii and O. ficus-indica. Both species are now invaded into large tracts of the vegetation-rich areas of south western mountains. Crassulaceae is a relatively small family in Saudi Arabia. All members (4 genera and 16 species) of this family in Saudi Arabia are leaf succulents and are seen among the high altitude areas of Hijaz Mountains. Umblicus spp. and Sedum spp. are moist loving plants, usually found among Pteridophytes.

Portulacaceae is represented by 2 genera and six species of annual or perennial herbs. Members of this family are characteristic of 2-phyllous floral involucre (sometimes considered as sepals) with scales or hairs at the leaf bases. The most prominent among them is the widely distributed, edible plant, Portulaca oleracea which is found in almost all semi aquatic habitats of Saudi Arabia. In Zygophyllaceae, two genera are succulent. Among these Nitraria retusa is reported from the eastern province while the genus Zygophyllum (Tetreana) with six species have a wider distribution, commonly seen in saline habitats.

Succulent species of Chenopodiaceae are also important in arid regions, some of which are extremely fleshy while a few genera, for example, Salicornia and Halocnemum have articulated stems with no leaves. In genera like Salsola, Haloxylon, etc the leaves are scale-like and are distributed in the arid regions or in the coastal and inland sabkhas (Salty areas).