Family composed of about 58 genera and about 1650 species of trees (rarely), shrubs, lianas and herbaceous plants, distributed mainly through warm and temperate regions worldwide. In North Africa it is represented by 11 genera, but there are only shrubs and subshrubs in Convolvulus.
The other species of the convolvulaceae family of the N of Africa, with some lignification, are found in the genus Seddera Hochst. should also be mentioned. It consists of 8 species, of which 2 are present in North Africa. They are small shrubs that sometimes, when there is no overgrazing, can exceed 0.5 m in height.
S. latifolia Hochst. & Steud., up to 40(60) cm in height; it is characterised by having young branches and greenish-whitish leaves covered by a mix of long and short hairs. Leaves (6-30 × 2.5-17 mm) from elliptical to obovate, obtuse or acute, sometimes apiculate at the apex, with petiole 1-5 mm long. Flowers axillary, solitary or in pairs, subsessile (pedicel <0.5 mm). Sepals (2.5-5 × 1-2.5 mm), unequal, from elliptical to oblanceolate, acute. Corolla 4.5-6.5 mm, white. Fruit a broadly ovoid capsule, hairy, 2-3 mm long. Seeds c. 1.5 × 2 mm. It grows in dry areas, of Saharo-Sindian distribution. In North Africa it can be found at least in the western Sahara, Egypt and Sudan.
S. arabica (Forssk.) Choisy (Cressa arabica Forssk.) is a subshrub, 20-35(60) cm in height, pubescent, with sparse hairs, woody old stems, young stems herbaceous and green. Leaves (0.5-15 × 0.3-0.8) with petioles 1-2 mm, elliptical, with rounded base and apex obtuse and mucronate. Flowers in cymes of a single flower, with peduncle 0.5-2 cm. Sepals (3-4 × 1.5-2 mm), from ovate to elliptical, with acute apex and coriaceous and pubescent base. Corolla 5-6 mm, white. Fruit a capsule, globose to broadly ovoid, glabrous. Seeds c. 2 mm, ovoid and black. It grows in forests and shrubland in rocky hills, distributed throughout the Arabian Peninsula and eastern tropical Africa, reaching in the N through the Sudanese regions of the Red Sea to Jebel Elba.
Rare but widely distributed species. Currently, they have not been assessed at a global level in the IUCN Red List of Threatened Species. In the Livre Rouge de la flore vasculaire du Maroc (Fennane, 2021) S. latifolia has been considered as Data Deficient (DD). In the Red List of vascular plants of Egypt (Flora Aegyptiaca Vol 1, 2000) S. arabica and S. latifolia are listed as “Endangered”.
Key to genera
1 Gynoecium with a single style Convolvulus
1 Gynoecium with 2 styles Seddera
Updated by: E. Salmerón, J.F. Mota & J. Charco.