Suillus luteus is a basidiomycete fungus, and the type species of the genus Suillus. It is a common fungus indigenous to coniferous forestsof Eurasia and North America, and introduced to southern Australia and New Zealand. Commonly referred to as slippery Jack or sticky bunin English-speaking countries, its names refer to the brown cap, which is characteristically viscid in wet conditions. The fungus fruits abundantly in autumn, and is harvested for food. The slime coating, however, may cause indigestion if not removed.


The cap is brown and up to 12 cm in diameter at maturity. The cap is initially hemispherical, later flattening out. It is slimy to the touch, bare, smooth, and glossy even when dry and the cuticle is easily peeled off. The tiny, circular pores of the tubes are at first light yellow but turn olive to dark yellow with maturity. The attachment to the stem is adnate. The stem attains a height of up to 10 cm and a width 3 cm. It is pale yellow and more or less cylindrical but may bear a swollen base. A white partial veil extends from the stem to the cap margin in immature specimens. At maturity the veil detaches from the cap and its remnant forms a ring around the stem. The underside of the ring is characteristically dark brown to violet. This species is one of the few members of the genus Suillus that sport such a ring. The white flesh of the entire fungus does not discolour when damaged, and it is soft particularly in mature specimens. It is frequently infested with larvae.

Similar species

Suillus luteus is often confused with Suillus granulatus, which is another common mushroom occurring in the same habitat. S. granulatus is yellow-fleshed and exudes latex droplets when young but most conspicuously, it bears neither partial veil nor ring. Other than that, Suillus luteus is unlikely to be confused with other mushrooms, especially if its preferred home under pine trees and the whitish partial veil are taken into consideration.

Distribution and habitatEdit

Suillus luteus can be found all over the northern hemisphere. It is found in coastal and montane pine forests and exhibits a tolerance of the northern latitudes. It is especially common in pine plantations and young pine forests. Suillus luteus forms mycorrhizal associations with various species of pine, which include Pinus sylvestris, Pinus nigra, and Pinus peuce in Europe, and Pinus resinosa and Pinus strobusin North America. It does not require a specific soil but seems to prefer acidic and nutrient-deficient soil. The fungus fruits in spring, summer and fairly prolifically in autumn, following periods of wet weather.

It has also been found under pine trees in introduced pine plantations in Australia, particularly in the Blue Mountains and Southern Highlands, as well as New Zealand and Argentinean Patagonia. There it can be picked around Easter.


Suillus luteus is an edible mushroom. Some authors regard it as an edible mushroom of low quality, while in Russia, where they are popularly known as maslyata "buttery ones", Slippery Jacks are frequently marinated and are considered a delicacy; they are also frequently consumed in soups, fried or stewed (from fresh or dried), known for their ability to maintain very light flesh color during cooking, similar to Boletus edulis, if the skin is peeled beforehand. It is known that this and other Suillus species may cause allergic reactions in some people. The fungus is better cooked before eating, and some authors recommend discarding the glutinous cuticle and tubes before cooking. However, some people may find them excessively slippery. Gastrointestinal symptoms could be due to high levels of arabitol.

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