Scleroderma (fungus)

Scleroderma is a genus of fungi, commonly known as earth balls, now known to belong to the Boletales order, in suborder Sclerodermatineae. The best known species are S. citrinum and S. verrucosum. They are found worldwide. Various members of this genus are used as inoculation symbionts to colonize and promote the growth of tree seedlings in nurseries.