Monadenium is a genus of about 50 species related to Euphorbia. Almost all the species are native to tropical East Africa, but strangely enough there are none in Madagascar. They vary in shape from geophytes that have a tuber and a skimpy annual structure that dies when the plant goes dormant, up to 5 m small trees. The genus name Monadenium comes from the Greek for ‘single gland’ referring to the flower structure of Monadenium coccineum the first species studied. Monadeniums should be kept warm in winter. They are very generally deciduous. They should be kept dry when dormant. Feed and water regularly when the plant is in leaf. Most Monadenium look best when grown in bright indirect light, but shade is generally tolerated. The plants tend to have more red when exposed to more sun light, and turn entirely green in the shade.

Monadenium guentheri is a perennial, succulent plant native to Eastern Africa. Cylindrical stems will reach up to 60cm tall with a stem diameter of 2.5cm to 3.25cms. The stems have rhomboidal or hexagonal tessellations with two 1-2 mm spines in each tessellation. Leaves are spatulate to obovate to 10cm long.