Although the plants are very variable in almost all respects, they are always completely and densely covered with white to reddish hairs (except the inside of the flowers). They have erect to creeping stems, 0.5-1.2 m tall and with egg-shaped to round leaves 16-40 cm long and 0.6-3 cm wide, often with an auriculate* base. The upper leaves are stalked, the ones near the base without stalks.
The inflorescenses are 15 cm wide and produce bulbils; the flowers have 1.4-3 cm long tubes and are red, pink, or yellow, often with red stripes. The species occurs in central, eastern and northern Madagascar, usually on damp or wet rock surfaces.
Several varieties have been described, but they are not upheld in the Illustrated Handbook of Succulent Plants.
*auriculate: with small roundish or ear-like appendages.
This species has a number of uncommon features, making it easy to recognise – once you know what to look for.
It is a small shrub up to 15 cm tall of which the short shoots are decked out with small spine-like projections and it has boat-shaped leaves to 1 cm long and 0.5 cm wide (those on upper shoots are more or less round). The leaves are covered with papillae which are more or less cobblestone-shaped, but much longer on the edges.
The flowers are solitary, pinkish-purple to almost white and to about 3 cm in diameter; they appear in July-September and are followed by fruits with 6 (instead of the usual 5) compartments.
The plants occur in deep soil usually covered with quartz pebbles, from Namaqualand to Clanwilliam.
Among all the various growth forms in the genus Euphorbia, the design of this species stands out as something singular.
The plants consist of a thick main stem covered with numerous branches up to 8 cm long, decreasing in length towards the top of the plant.
In this way, a compact cone is formed up to 60 cm tall and to 25 cm across at base. In some cases however, the plants are not shaped quite so neatly, resulting in a far less appealing and peculiar habit of growth (see pictures).
The spines are in fact sterile flower stalks; they are 0.8 to 7 cm long and arise from both main stem and branches.
The species occurs on stony slopes and flats from Steinkopf in Namaqualand to the western Little Karoo.