Adenium

Adenium obesum  Roemer & Schultes 1819
The thick trunk up to 15 ft tall, produces clusters of dark-green oval leaves with a pronounced mid-vein. As with other members of the Apocynaceae (Dogbane Family), the showy white, pink or red flowers have 5-fold symmetry. Native to Aarabia, Socotra and tropical Africa and naturalised elsewhere across the tropics.
 
Sub-species include:
Adenium obesum ssp. boehmianum (Southern Africa, Namibia, Angola)
Adenium obesum subsp. obesum (from Mauritania and Senegal to Sudan)
Adenium obesum subsp. oleifolium (South Africa, Botswana)
Adenium obesum subsp. socotranum (Socotra)
Adenium obesum subsp. somalense (Eastern Africa)
Adenium obesum ssp. swazicum (Eastern South Africa)

Cultivation:
Adeniums are widely grown as tender houseplants and will not tolerate any frost or even cold conditions. A very free-draining potting mixture should be used and even then the plants should be watered carefully. Much work has been done to produce a variety of showy cultivars by hybridising between the different sub-species. Desirable varieties will probably not come true from seed so they are propagated by grafting as cuttings may be slow to produce the attractive bottle-shaped trunk.
 
Adeniums contain cardiac glycosides and should be regarded as poisonous. They have been used as components of arrow poisons.