Suillus luteus

Suillus luteus is a pored mushroom of the genus Suillus in the Suillaceae family. It has a white stalk with a distinctive ring and an often slimy brown cap, earning it the name Slippery Jack in North America. When dry the cap may be sticky, hence an alternate common name Sticky bun. S. luteus is an edible mushroom that can be found all over the northern hemisphere and often grows in a symbiosis (Mycorrhiza) with pine. The slime coating, however, may cause indigestion if not removed.

Description
The cap is yellow to chocolate-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. The pores are at first light yellow but turn olive to dark yellow later on and grow down the stalk a little. The stalk grows to a height of about 6 to 12 cm and to a width of about 1 to 2.5 cm. Usually it looks like a cylinder, sometimes enlarges at the bottom so that it has more of a pear shape. A white velum connects a the stalk to the cap when young. At maturity the remains of the velum form a ring around the stalk; the Slippery Jack is one of few mushrooms of the genus Suillus that sport such a ring.

Occurrence
Suillus luteus can be found all over the northern hemisphere. It is found in pine forests from the coast to the mountains and exhibits a special liking for the cold-temperate climate. It does not require a specific soil but seems to prefer acidic and nutrient-deficient soil. In September and October it can frequently be found in clusters.

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

Similar species
Suillus luteus is often confused with Suillus granulatus, which does not have a ring around its stalk and prefers rather alkaline soil with relatively high lime content. Other than that, Suillus luteus is unlikely to be confused with other mushrooms, especially if its preferred home under pine trees and the whitish velum are taken into consideration.

Use
This mushroom is edible but may occasionally cause allergic reactions in some people similar to those caused by Paxillus involutus. The pores should be removed prior to preparation and the fungus is better cooked before eating. In Russian, Slippery Jacks are known as maslayata ("buttery ones"). They are frequently marinated and are considered a delicacy. However, some people may find them excessively slippery. Gastrointestinal symptoms could be due to high levels of arabitol.