Suillus viscidus
Description
Suillus viscidus (syn. Suillus laricinus and S. aeruginascens) is an edible, uncommon mushroom in the genus Suillus. It associates with larch and is found throughout Europe and in Japan.
This mushroom has a viscid to slimy, gray to olive-brown or darker cap, the edge of which sometimes is adorned with bits of veil tissue.
The tubes and pores are whitish to gray, not yellow as in most suilluses, and stain blue when bruised. The stipe is whitish above the slight ring or ring-zone. The lower stipe is viscid and similar in color to the cap. The flesh is white to yellowish and stains blue when bruised or cut.
Interestingly, S. viscidus stains waxed paper or white office paper blue. Look for it in late summer and fall. It has sometimes been placed in the genus Fuscoboletinus.
Common names: Sticky Bolete, Grayish Larch Bolete.
Mushroom Identification
Cap
Hemispherical when young, expanding to become broadly convex or almost flat, 6 to 10cm in diameter; off white when young, yellowing and later darkening to ochraceous grey with age; covered in a thick coating of viscid glutinous translucent slime that remains tacky even in very dry weather.
Tubes and pores
Beneath the cap, a white veil covers the young pores of this bolete, fracturing to leave a thin stem ring that soon collapses against the stem and becomes discolored clay brown by falling spores. The off-white to pale grey tubes are adnate or slightly decurrent to the stem; they terminate in oval pores that are concolorous with the tubes.
Stem
Cylindrical or slightly clavate, 1 to 2cm in diameter and 5 to 10cm tall, the stem is whitish above the ring zone and noticeably darker, often with an olive tinge below.
Spores
Ellipsoidal to sub-fusiform, smooth, 8-14 x 4-5μm.
Spore print
Clay brown.
Odor and Taste
Odor not distinctive; taste slightly acidic.
Habitat & Ecological role
Mycorrhizal; beneath larch trees, usually on calcareous or sandy soils.
Season
August to October.
Similar Species
Suillus grevillei has a bright yellow-orange cap and angular pores; it also occurs under larch.
History
When in 1753 Carl Linnaeus described this bolete he called it Boletus viscidus. The currently accepted scientific name of the Sticky Bolete, Suillus viscidus, dates from a 1796 publication by the French mycologist Henri François Anne de Roussel (1748 - 1812).
Synonyms of Suillus viscidus include Boletus viscidus L., Boletus aeruginascens Secr., Boletus laricinus Berk., Ixocomus viscidus (L.) Quél., Suillus laricinus (Berk.) Kuntze, Suillus aeruginascens Secr. ex Snell, and Fuscoboletinus aeruginascens (Secr. ex Snell) Pomerl. & A.H. Sm.
The specific epithet viscidus means viscid, of course, while the generic name Suillus comes from the Latin noun sus, meaning pig. Suillus, therefore, means 'of pigs' (swine) and is a reference to the greasy nature of the caps of all fungi in this genus.
Photo sources:
Photo 1 - Author: Dezidor (CC BY-SA 2.5)
Photo 2 - Author: Strobilomyces (CC BY-SA 3.0)
Photo 3 - Author: Jerzy Opioła (CC BY-SA 4.0)
Photo 4 - Author: Suillus_viscidus.jpg: Dezidorderivative work: Ak ccm (talk) (CC BY-SA 2.5)
Photo 5 - Author: Jerzy Opioła (CC BY-SA 4.0)