Carissa bispinosa

Carissa bispinosa, commonly the num-num, is a spiny evergreen shrub, sometimes a scrambler. Occasionally it becomes a small tree of up to 5 m in height, usually less than half that (SA Tree List, 640.1). This is a heterogeneous species varied in appearance. The plant is multistemmed, resprouts after fire. The plant exudes a milky latex when the skin is damaged. This is common in plants of the family Carissa belongs to, the Apocynaceae. The plant exudes a milky latex when the skin is damaged. This is common in plants of the family Carissa belongs to, the Apocynaceae. The bark on the much-branched stems is initially green, becoming partly grey and wrinkled. Forked spines are conspicuous upon the stems. 

The photo was taken near the Seweweekspoort where both C. bispinosa and C. haematocarpa used to grow, but since the documented disappearance of C. haematocarpa into C. spinosa, the problem of distinguishing between the two is something of the past. Those who took the trouble to master the differences, take their time in adapting to the lumping. It's harder to deal with new names or additional ones when separations occur. Speciation is all about splitting, but when to agree that it should become official, is always a talking point. Like the many people commenting on the differences among all the plants called C. bispinosa. Don't forget that C. wyliei has also disappeared into C. bispinosa.

Appearance differences between plants occur on a continuous basis, including many grey areas of partial certainty, rather than clear definitional lines between species. The differences multiply with the appearance of new adaptations surviving in nature's diverse ecological settings. The human decisions to separate the known living things into more categories, as reflected in the official nomenclature developed by them, inevitably multiply the grey areas of uncertainty. And it is such a good thing that genetics separate siblings in looks, otherwise there would not be much point in giving them all different names.

The species distribution of C. bispinosa is widespread across South Africa, barring some western and central parts. The plants are found in the Richtersveld of the Northern Cape, the Western Cape, the Eastern Cape, KwaZulu-Natal, all the provinces north of the Vaal River, as well as in several African countries. 

The habitat includes dry woodland, forest, bushveld, thicket, grassland and coastal scrub, also along forest margins and the under-storey of evergreen forests. Coping in all these places and more, gives the plants many shapes and sizes. The habitat population is deemed of least concern early in the twenty first century (Euston-Brown and Kruger, 2023; Le Roux, et al, 2005; Coates Palgrave, 2002; Van Wyk and Van Wyk, 1997; Pooley, 1993; iNaturalist; https://redlist.sanbi.org).