Rhizopogon obtectus or Choiromyces venosus

There is no true cap. The fruiting body is tuber-shaped, round or irregularly round, 1 to 4 centimeters across, resembling a small potato or a truffle. The surface is smooth or covered with fine pressed-down fibers (rhizomorphs), whitish or yellowish at first, turning reddish-brown or olive-yellow with age and where handled. The entire fruiting body is closed, with no openings.

The fruiting body is an irregular, tuber-like lump, 2–8 cm (sometimes up to 12 cm) across. When young it’s white or cream, with a smooth surface. With age it turns yellowish-brown with reddish-brown blotches. The surface is matte and may wrinkle slightly as it matures.

There is no hymenophore in the usual sense. The spores ripen inside the closed fruiting body, in a maze-like chambered tissue (the gleba). In young mushrooms it is white and firm; as it matures it turns yellow, then brown and jelly-like, and later powdery. The spore print is olive-brown. A chambered inner tissue with no true pores or gills is a hallmark of the underground rhizopogons.

The spore-bearing layer is inside — in a young mushroom the “flesh” is uniformly white; as it matures, distinctive labyrinth-like, net-like darker veins develop, running through the white base. Cut open, a mature mushroom shows a striking marbled pattern — which is where the name “meandriformis” comes from (after the meanders of a river).

There is no distinct stem; the fruiting body is attached to the soil by thin whitish cords (rhizomorphs), especially noticeable at the base. The whole structure is a single solid tuber with no division into cap and stem, which is exactly what sets Rhizopogon apart from the familiar cap-and-stem mushrooms.

There’s no stem — the fruiting body is hypogeous (underground), fully buried in the soil. It is attached to the substrate by thin mycelial strands.

The flesh (gleba) of young mushrooms is white, firm and uniform, with tiny maze-like chambers. This is the only stage at which the mushroom is edible. As it matures, it turns yellow, then brown, becomes jelly-like and unfit to eat. White young flesh in cross-section is your guarantee of edibility; any darkening means the mushroom is overripe.

In young mushrooms the flesh is solid white, dense and meaty. In mature ones it’s a white base with a network of yellow-brown or grayish veins. The texture resembles a firm cheese.

The smell is faint, pleasant and mushroomy, becoming stronger and not always pleasant in mature specimens. The aroma is not a defining feature; you recognize this mushroom by its underground lifestyle, its closed tuber-like fruiting body with no cap or stem, and its link to pine.

The smell is strong and peculiar — like a mix of Camembert cheese, canned mushrooms and raw potato. In fresh specimens it’s pleasant; in overripe ones it becomes sharp and unpleasant. The taste is mild, with a nutty note.