Paxillus involutus is one of the most abundant mushrooms. Its cap is viscid in the centre and woolly at the edges and in colour is almost identical to its short stipe. The yellowish flesh has a slightly bitter taste and smell. If it is bruised the whole fruit-body turns a rust colour and later brown.

However, this mistake can be avoided if some care is taken. llylopillts felleus is characterized not only by its bitter taste, but also by its pale pink tubes which, when bruised or old, become a rusty brown and are never yellow-green like the tubes of the ripe fruit-bodies of Boletus edulis. These tubes are at first white and angular, whilst the stipe is covered by a network of veins.

It is recommended therefore that Paxillus involutus should not be collected. Paxillus atrotomentosus is often seen on the stumps and dead roots of coniferous trees. It is not poisonous, but is a poor quality. The taste and smell of its flesh is bitter and acidic.

There are not many other mushrooms as common as the Honey fungus. In September its clusters usually cover the stumps, roots and bases of live or dying deciduous or coniferous trees. Less frequently it occurs as early as June. It is a dangerous parasite which damages fruit trees as well as many woodland species. When tree trunks are attacked, they become covered with white sheets of mycelia or with multi-branched ribbons of this fungus, which are brown or black on the surface and white inside and which penetrate the bark and base of the tree.

An interesting microchemical reaction can be observed on the flesh of fresh fruit-bodies: if a drop of soda solution comes into contact with its flesh, which is originally orange-yellow, it turns violet; if coated with a solution of green vitriol it becomes deep green and in contact with a weak solution of ammonia it turns a vivid carmine. A change in the colour of the flesh is also noticeable when the fruit- body is drying out, during which process both the skin on the cap and stipe as well as the flesh itself turn pink.

Like Goniphidius glutinosus, Gomphidius mains is also an excellent edible mushroom and can be prepared in a number of ways. It turns violet when boiled and when pickled in vinegar it becomes almost black. This is a useful feature as it adds to the varied colour of any mushroom mixture.