Desert truffle

What is a desert truffle?

Desert truffle is the shared name for underground fungi in the genus Terfezia; in Turkey they go by local names such as domalan, keme, dolaman, kemeye, tombalak and geme. Turkish Wikipedia's domalan article lists Terfezia arenaria, T. boudieri, T. claveryi, T. leptoderma and T. leonis, along with the white desert truffle Tirmania nivea. The species most often named in Turkey are Terfezia boudieri and Terfezia claveryi.

Despite the name, a desert truffle is not a true truffle. True truffles belong to Tuber, live with trees such as oak and hazel and smell strongly. Desert truffles belong to Pezizaceae, live with low shrubs and have a mild smell. We cover true truffles on our truffle page, and the difference is also explained in our article on domalan.

The fruit body, the part we see, is a tuber that forms a few centimetres below ground. There is no cap, stem or gills; the outside is pale brown and the inside cream, marbled with pale veins. So unlike the capped mushrooms on our site, it is described by its outer skin and its inside.

Where does the desert truffle grow in Turkey?

The desert truffle grows on dry steppe, in sandy, quick-drying soil. Wikipedia reports desert truffles from arid zones of the Mediterranean basin, North Africa and the Middle East, includes Turkey in that range and shows a desert truffle photographed at Avanos.

In Turkey, domalan is known around Konya, Karaman and Şanlıurfa (Turkish Wikipedia). A study by Muğla Sıtkı Koçman University researchers in Denizli recorded Terfezia boudieri alongside true truffles. The seven Terfezia claveryi observations on our map are from Ankara and Konya. You can see every record on our mushroom map of Turkey; a blank area does not mean the fungus is absent, only that no one has recorded it there.

The host plant decides where to look. The desert truffle mostly forms mycorrhizae with rockroses (Helianthemum); Turkish Wikipedia calls the plant kumi otu. Wikipedia adds that partnerships with Cistus, oaks and pines have also been reported.

When is desert truffle season?

Domalan appears in spring, from late March to May. Turkish Wikipedia says it comes up after spring rain, and the Turkish records on our map are from April and May.

A year's crop is decided by the previous autumn and winter, not by the spring itself. Sources gathered by Wikipedia say desert truffle yields depend largely on autumn and winter rainfall: plenty after a wet winter, few or none after a dry one. So the same spot does not give the same amount every year. Our mushroom calendar shows what appears in each month.

How do foragers find desert truffles?

Desert truffles are found by the marks they leave on the ground, not by sight. The growing tuber pushes the soil up, so foragers look for small mounds and cracks around the host plant (Turkish Wikipedia, Wikipedia). Unlike true truffles they are rarely hunted with dogs, because the smell is weak.

Digging without damaging the tuber and nearby roots, filling the hole back in and leaving small, unripe tubers in place protects the patch for the next year. Before going out, read our mushroom foraging guide for kit and rules.

Is the desert truffle poisonous, and what is it confused with?

A correctly identified desert truffle is edible; Turkish Wikipedia lists it among edible mushrooms. The danger is mistaking a poisonous tuber-like fungus for domalan.

The main confusion is with earthballs (Scleroderma). According to First Nature, the common earthball (Scleroderma citrinum) has a thick, hard, scaly skin and an inside that is white at first, then turns purple-black and powdery. The desert truffle has a thin skin that peels easily and a pale, veined inside. The scaly earthball (Scleroderma verrucosum), recorded in Turkey, can also be half buried. Anyone who cuts a tuber and finds a dark, unveined or powdery inside does not eat it. See our poisonous mushrooms page for the full list.

Do not rely on one feature; skin, inside, smell and habitat are judged together. If in doubt, do not eat it, and if symptoms follow, call 112 or 114 at once.

How do you tell a desert truffle from a true truffle?

The easiest way to tell them apart is by habitat, skin and smell. The desert truffle comes up in spring on dry steppe, in sandy soil at the foot of low shrubs such as rockroses. True truffles ripen in woodland among the roots of oak, hazel or beech, in calcareous soil, in summer or winter depending on the species.

The skin is a clear clue. A desert truffle has a thin, smooth or slightly rough skin, pale brown to reddish, that peels easily. Summer and black truffles are covered in hard black warts. Both are veined inside, but the desert truffle stays cream or pale pink, while black truffles darken as they ripen.

Smell is the last test: ripe true truffles smell strong and distinctive, which is why dogs find them; desert truffles smell mild and are found by the marks in the soil. These differences separate the two groups; to rule out poisonous earthballs, use the warnings above as well.

Is it legal to pick desert truffles in Turkey?

Picking a little for your own table is a common tradition, but commercial picking and sale of produce from forest and pasture land is regulated. Non-wood forest products (mushrooms included) from state forests are managed under Turkey's Forest Law No. 6831 and General Directorate of Forestry rules; anyone planning to pick commercially checks with the local forest enterprise office. We also cover this in our article on where truffles grow in Turkey. We do not quote prices.

Can desert truffles be cultivated?

Desert truffles cannot be grown at home or from a kit; they are only being trialled in fields with inoculated plants. Wikipedia says Israeli researchers are trying to turn Terfezia boudieri into a crop. Rockrose seedlings with inoculated roots are planted in suitable soil and, depending on rain, a harvest is hoped for over several years. We describe the same method for true truffles in our truffle growing article; species you can grow at home are on our grow at home page.

How is desert truffle used in the kitchen?

Desert truffles are cleaned well and eaten cooked. In the recipes shared on University of Wisconsin mycologist Tom Volk's pages, the tubers are scrubbed with a soft brush or washed carefully to remove sand and peeled if needed; Turkish Wikipedia also notes that the skin peels easily. According to Wikipedia, desert truffles have little flavour of their own and take on the taste of what they are cooked with, which is why the Romans used them as a flavour carrier in spiced dishes. So rather than being shaved raw like true truffles, they are sautéed in butter with onion and added to eggs, soups or rice. Our desert truffle scrambled eggs, adapted from Tom Volk's page, is the simplest example.

Keep cleaned desert truffles in a paper bag rather than plastic in the fridge and cook them within a few days; plastic traps moisture and speeds spoilage (Penn State Extension, general advice for mushrooms). Only cook tubers that have been identified with certainty; a white or creamy interior is a good sign but not enough on its own.