Suillus granulatus
Suillus granulatus is a species of fungus in the genus Suillus. It has been commonly known as the weeping bolete, the butterball bolete, or the granulated bolete. It is a pored mushroom similar to S. luteus, but can be distinguished by its ringless stalk.
The species often grows in a symbiosis with pine. It is native to the Northern Hemisphere and has been introduced elsewhere. It is edible.
Taxonomy
Suillus granulatus was first described by Carl Linnaeus in 1753 as a species of Boletus. It was given its current name by French naturalist Henri François Anne de Roussel when he transferred it to Suillus in 1796. Suillus is an ancient term for fungi, and is derived from the word "swine". Granulatus means "grainy" and refers to the granular dots on the upper part of the stem.However, in some specimens the granular dots may be inconspicuous and not darkening with age; thus the name S. lactifluus, "oozing milk" was formerly applied to this form as it is not notably characterized by granular dots.
Previously thought to exist in eastern North America, that species has now been confirmed to be the rediscovered Suillus weaverae.
Description
The orange-brown, to brown-yellow cap is viscid when wet, and shiny when dry, and is usually in diameter. The pale yellow stem is about tall wide, and of uniform thickness; it has tiny brownish granules at the apex and lacks a ring. The tubes and pores are small, pale yellow, and exude pale milky droplets when young. The flesh is also pale yellow.Similar species
Suillus granulatus is often confused with S. luteus, which is another common and widely distributed species occurring in the same habitat. S. luteus has conspicuous a partial veil and ring, and lacks the milky droplets on the pores.Also similar is S. brevipes, which has a short stipe in relation to the cap, and which does not ooze droplets from the pore surface. S. pungens is also similar.
Bioleaching
is the industrial process of using living organisms to extract metals from ores, typically where there is only a trace amount of the metal to be extracted. It has been found that S. granulatus can extract trace elements from wood ash and apatite.Habitat and distribution
Suillus granulatus grows with Pinus on both calcareous and acidic soils, and sometimes occurs in large numbers. It is the most widespread pine-associating Suillus species in warm climates.The species is native to the Northern Hemisphere. It is associated with Japanese red pine in South Korea. It has been introduced to South Africa, Hawaii, Australia, New Zealand, Argentina, and Chile, and the Falkland Islands.