Cotyledon tomentosa is a species of flowering plant in the family Crassulaceae, native to South Africa.

In its native habitat, the Little Karoo region of South Africa, Cotyledons usually grow in rocky quartz fields where they have excellent drainage provided by very porous soil.

Cotyledon tomentosa is a perennial evergreen shrub, which is a member of the Crassulaceae family of succulent flowering plants.

[7] C. tomentosa has red, orange, or yellow bell-shaped flowers between July and September,[12][7] and there are two recognized subspecies, subsp.

[7][13] In 1936, Karl von Poellnitz noted the conflict and gave the taxon a new name, Cotyledon ladysmithiensis,[8] for its native range near the town of Ladismith, South Africa.

"[7] Cotyledon tomentosa is native to the semidesert Little Karoo region located in the southern parts of South Africa, from Ladismith to Steytlerville.

tomentosa is found near Calitzdorp, Willowmore, and Steytlerville,[15] in the gravely soil of arid thicket, in slopes of sheltered ravines.

Cotyledon species are known to contain cardiac glycosides, including bufadienolides,[16] which are highly toxic to cattle, sheep, goats, and other livestock.

[17] On the World Health Organization toxicity scale, cardiac glycosides are considered Class Ia, "extremely hazardous,"[18] and a dose of only 1.0 g/kg body weight of a related species, Cotyledon orbiculata, was lethal when fed to sheep.

[19] Bufadienolides are classified as neurotoxins because they are strong inhibitors of sodium potassium pumps which are central to the function of animal nervous systems.

[20] These toxins persist in the flesh of livestock afflicted with krimpsiekte, even after cooking, and dogs who consume this meat can exhibit similar neuromuscular symptoms.

Water with caution in winter, as the plant can lose its roots if the soil stays cold and wet for extended periods.