Suillus luteus, also known as Slippery Jack Bolete, is a medium to large bolete with a slimy, brown cap and a short to stubby stem which has brown granular dots and a well-developed ring. The mushroom is mycorrhizal, meaning it forms a mutually beneficial relationship with the roots of pine trees. Suillus luteus can be found in coniferous forests, especially those dominated by pine trees, in various regions around the world.

Cap chestnut, rusty, olive-brown, or dark brown in colour. It has a distinctive conical shape, later flattening out. It is slimy to the touch, bare, smooth, and glossy even when dry, and the cuticle is easily peeled off. Flesh whitish with a yellow tinge, unchanging, moderate and soft, unchanging when cut. Pores tiny, circular, initially yellow but turn olive to dark yellow with maturity. Like the skin of the cap, they can be readily peeled away from the flesh. Tubes concolourous with pores, adnate. Stem pale straw-yellow at first but later darkening, more or less cylindrical but may bear a swollen base. A membranous partial veil initially links the stipe with the edge of the cap. When it ruptures, it forms a membranous, hanging ring with is at first whitish, darkening with age, vinaceous-brown below and large. Spore print ochraceous or buff coloured.

Microscopic Features: Spores are sub-fusiform, exhibiting a smooth surface, with dimensions of approximately 8-10.5μm in length and 3-3.5μm in width.

Suillus luteus on the Nature First Web site.
Suillus luteus on the MushroomExpert.Com Web site.