Cnidoscolus

Cnidoscolus is a genus of flowering plants in the spurge family, Euphorbiaceae. The genus comprises several species distributed across the tropical and subtropical Americas, from the southern United States to northern Argentina, with a concentration in the Caribbean and Central America. Many species grow as shrubs or small trees and are often armed with spines or stiff hairs; they exude a milky latex when damaged. Leaves are variable in form, with some species bearing large, deeply lobed leaves, while others have more simple shapes. Flowers are small and inconspicuous, produced in clusters, and the fruit is typically a small capsule containing seeds.

Cnidoscolus species are known for stinging or irritating properties due to specialized trichomes on stems and leaves, particularly in the nettle-like species such as Cnidoscolus urens and Cnidoscolus stimulosus, which can cause dermatitis on contact. Handling caution is advised.

In human use, some species are valued as food. The most widely cultivated is Cnidoscolus aconitifolius, commonly called chaya or tree spinach; its leaves are highly nutritious and cooked before eating to remove toxins and improve palatability. Other species are less widely utilized and are typically grown as ornamentals or for hedging.

Selected species: Cnidoscolus aconitifolius (chaya, tree spinach); Cnidoscolus stimulosus (bull's-horn nettle); Cnidoscolus urens (burning nettle).