Convolvulaceae de Jussieu 1789
The Convolvulaceae is a family of about 85 genera and 2,800 species of twining vines or shrubs, sometimes with milky sap, and simple often heart shaped alternate leaves, although sometimes lobed. Flowers are often large and showy with a trumpet-shaped corolla and usually bisexual. The flowers of many species are only open during the morning, hence the common name "Morning Glory". Some morning glories are pernicious weeds, especially in warm climates and a few are even frost hardy.
Succulent genera: Although most morning glories are non-succulent, several choice caudiciforms are found in the genera Ipomoea, Merremia, Stictocardia and Turbina. These succulent plants are usually grown with the tuber exposed on the surface of the soil.
Ipomoea Linnaeus 1753 (morning glories, bindweeds)
Ipomoea includes over 500 species of flowering plants. This is the largest genus in the Family Convolvulaceae and includes diverse lifestyles of annual and perennial twining vines, shrubs and caudiciforms. Many species have large, trumpet-shaped flowers which may be white or brightly coloured and some species are of horticultural interest as ornamental plants.
Ipomea bolusiana Schinz 1888
is a choice tender caudiciform with stems bearing narrow palmate leaves dissected into 3-9 lanceolate sections. The flowers are large pink trumpets often candy-striped with deeper pink.
Native to Southern Africa and Madagascar.
Turbina holubii Meeuse 1958 Syn. Ipomea holubii Baker 1894
Is very similar to I. bolusiana but with longer trailing stems and broader leaf segments.
Native to Southern Africa.
Ipomoea batatas (Linnaeus ) Lamarck 1791 (sweet potato)
is of considerable economic importance and has been cultivated for at least 4500 years for its sweet starchy tubers with a significant free sugar content. The flesh of the tubers is coloured yellow to orange by carotenoids (Vitamin A precursors), which make a valuable contribution to the diet. Sweet potatoes are native to tropical America but were transported to many Pacific islands by migrating Polynesians.
Cultivation: Sweet potatoes ( Ipomoea batatas ) make interesting tender plants for a sunny window-ledge and will produce pretty pink trumpet-shaped flowers. If soaked daily, tubers bought from the supermarket will sprout under warm conditions and can then be planted on the surface of free-draining compost for an instant caudiciform plant.
As with any caudiciform succulents, it is essential to use a very free-draining compost and water carefully, especially out of the active growing season or when the weather turns cold. It may help to separate the tuber from the compost with a layer of free-draining grit. Full or partial sun promotes prolific flowering and seed pods are usually formed freely with fertile seeds.