Euphorbia heptagona colourful stem-tips

Euphorbia heptagona branches much and reaches heights around 1 m. The species is dioecious, meaning that male and female flowers occur on separate plants. The grey-green stems have six to ten ridges, the name heptagona suggesting a modus of seven.

On the plant in picture the spines on the stem ridges start off yellow, pointing up on green ridge tubercles. The spines are mostly pale for a short while after changing direction from upwards to outwards. Then the more durable brown or red brown colouring settles in. The spines will later become whitish grey as they age and dry. Still later the dead ones drop off, leaving the ridges bare.

When the plant is growing but not flowering, the spines are spines throughout. During bloomtime the spines are cyathia on pedicels, morphing into spines as well, after the flowers turned fruits are gone.

This plant was photographed at Kirstenbosch. It was marked as E. heptagona var. heptagona at the time. There used to be four more varieties of E. heptagona: var. dentata (probably confined to the Eastern Cape), var. ramosa, var. subsessilis and var. viridis. None of the varieties is still recognised. It is good to remember that this species is variable, the variability partly associated with geographical distribution.

The cyathia are green, yellow-green or reddish and 5 mm wide. Flowering occurs from winter to spring (Euston-Brown and Kruger, 2023; Smith, et al, 2017; Vlok and Schutte Vlok, 2015; Bond and Goldblatt, 1984; iNaturalist; Wikipedia).