Berkheya is a genus of approximately 75 species of flowering plants in the family Asteraceae (daisy family), order Asterales. The genus is strongly centered on Africa, with the great majority of its diversity — around 71 species — found in South Africa, and the remainder distributed across tropical Africa.
Plants in the genus are typically thistle-like in appearance, with spiny leaves and composite flower heads characteristic of the Asteraceae. Most species bear yellow ray florets, giving them a sunflower-like aspect; a small number produce white rays, while the ornamental Berkheya purpurea is notable for its distinctive light purple to mauve florets.
The genus includes both wildland species and a handful known as weeds. Berkheya purpurea is widely cultivated as an ornamental for its unusual flower color. Berkheya coddii has attracted scientific attention as a hyperaccumulator of nickel: concentrations in leaf tissue can reach 7.6% of dry weight, among the highest recorded for any plant, and the species is studied for phytoremediation potential on nickel-contaminated soils.
Several Berkheya species have documented ecological relationships with insects. Members of the genus are associated with weevils in the genus Larinus, and the tephritid fruit fly Urophora agromyzella also occurs on these plants.
Etymology
The genus Berkheya was named in honor of Johannes le Francq van Berkhey (1729–1812), a Dutch naturalist, poet, and artist known for his encyclopedic work on the natural history of the Netherlands.
Distribution
Berkheya is an African genus: of the approximately 75 recognized species, around 71 are native to South Africa, with the remaining species distributed across tropical Africa, particularly in southern and eastern regions.
Ecology
Berkheya coddii is a highly studied nickel hyperaccumulator, capable of concentrating nickel in leaf tissue to levels reaching 7.6% of dry weight — one of the highest values known in the plant kingdom. This property has made it a candidate species for phytoremediation of nickel-contaminated soils. Across the genus, plants support specialist insect communities, including weevils of the genus Larinus and the tephritid fruit fly Urophora agromyzella.
Cultivation
Berkheya purpurea, sometimes called the purple berkheya or African thistle, is the most widely grown ornamental species, valued for its unusual mauve to light purple ray florets set against spiny, thistle-like foliage. It is grown in herbaceous borders in temperate gardens where it tolerates well-drained soils and full sun. Some other species in the genus can behave as weeds outside their native range.
