Notes on the Kalahari desert truffle, Terfezia pfeilii

Ascocarps of the Kalahari desert truffle, T. pfeilii, were discovered attached by a ‘stalk’ consisting of sand particles and a mesh of mycelial tissue. Rhizomorphs were found in the vicinity of this ‘stalk’. The ascocarps occurred mainly on the southern, shady, side of shrubs and trees, the roots of some of which appeared to have developed mycorrhizal associations. Local lore maintains that truffles are found under grasses. Perennial Gramineae were found in close proximity to all the T. pfeilii ascocarps, some of which were mycorrhizal. However, roots of bushes and trees were also invariably found at a shallow depth beneath each truffle. At one site, over 20 fruiting bodies were found in a 20 m² watered lawn of Cynodon dactylon under the shade of an Acacia erioloba. Soils at T. pfeilii sites had a lower pH and lower calcium content than those reported from sites where northern African members of this genus occur.