Slippery jack

Description

The slippery jack has a slippery, sticky, shiny cap 4–12 cm across, chocolate-brown or yellow-brown, and lemon-yellow tubes. It is easiest to recognise by the membranous ring on the stem, brown-violet underneath, and by the brown granules above the ring.

It grows from May to autumn under pines, often in young pine stands, and is very common in Poland. In a warm autumn it can be found even in December.

It is distinguished from the granulated bolete by the ring on the stem. Before preparation the slimy cuticle must be removed from the cap, and young specimens are better than old, soft and often wormy ones. If you are not sure of the species, do not pick it.

Identification features

Cap

Diameter 4–12 cm, rarely up to 20 cm (descriptions give different ranges); young ones hemispherical or conical, then flattened. Colour chocolate-brown, chestnut, rusty, olive-brown or dark brown, sometimes yellow-brown. Cuticle bare, smooth, slimy, sticky, shiny even when dry, easily separating from the flesh.

Hymenophore (underside of the cap)

Tubes 3–12 mm long (descriptions give different ranges), lemon-yellow, attached to slightly running down; in young fruiting bodies covered by a white membranous partial veil. Pores small (about 3 per mm in young ones, 1–2 in mature ones), at first round and yellow, then angular and olive to dark yellow; together with the tubes they easily separate from the flesh.

Stem

Height 3–11 cm, thickness 1–3 cm, cylindrical, hard and solid, pale yellow, sometimes with a slightly thickened base, without a bulb or volva. A characteristic membranous, hanging ring: whitish above, brown-violet underneath; gelatinous when wet. Above the ring the stem has brown glandular dots, below the ring dirty white, sometimes with slimy brownish streaks.

Flesh

White-yellowish to white, at first firm, then soft, does not change colour when damaged (according to some descriptions slightly brown only at the bottom of the stem). Taste pleasant, smell indistinct. The flesh of mushrooms you are not sure about should not be tasted.

Spore print and spores

Spore print rusty-ochre, ochre or clay-coloured (descriptions give different colours). Spores smooth, elongated elliptical, 7–11 × 2.5–4 µm (descriptions give different ranges).

Habitat and distribution

Ecology. Mycorrhizal fungus (ectomycorrhiza), mainly with pines (Scots, black, Macedonian P. peuce, in North America red and Weymouth pine); a pioneer species, occurring in young stands and in early stages of succession, prefers acidic and poor soils. Produces siderophores; protects pines from heavy metal toxicity.

Distribution. The whole Northern Hemisphere in the temperate climate (native in Eurasia from Ireland to Korea), introduced with pines to both Americas, southern Africa, Australia and New Zealand. Very common in Poland. Not legally protected.

Fruiting. From May to autumn; in a warm autumn and late winter fine specimens have been found as late as mid-December.

What can it be confused with?

• Suillus granulatus (granulated bolete) — No partial veil and no ring; young fruiting bodies with milky droplets on the pores; flesh yellowish.
• Suillus collinitus (Polish: maślak rdzawobrązowy) — Also under pines, but the cap is paler and there is no ring.
• Suillus grevillei (larch bolete) — Grows under larches; cap yellow.
• Gomphidius glutinosus (slimy spike-cap, young fruiting bodies) — Similar from above, but has gills, not tubes, under the cap.
• Suillus albidipes — When the veil separates from the stem, fruiting bodies of S. luteus can resemble it; S. albidipes has no glandular dots on the stem.
• Suillus tridentinus — Caution: similar protected species (strict protection in Poland), not included in the Atlas. Cap orange to rusty with darker fibrils, pores orange; under larch, mainly on calcareous soils in the mountains. Do not pick.
• Suillus sibiricus — Caution: similar protected species (partial protection in Poland), not included in the Atlas. Cap yellow with brownish spots, stem with brown dots; grows only under Swiss stone pine (in Poland in the Tatra Mountains). Do not pick.
• Suillus flavidus — Caution: similar protected species (partial protection in Poland), not included in the Atlas. Small, pale yellow, slimy, with a gelatinous ring; in bogs under pine, among sphagnum. Do not pick.

Never rely on a single feature. If you are not sure — do not pick it; show the mushroom to a qualified mushroom expert.

Interesting facts

• On 8 May 1959 the Polish post issued a stamp with the slippery jack, with a face value of 30 gr, in the “Mushrooms of Poland” series; it was printed in a run of 416,000.
• In Ecuadorian plantations of Pinus radiata the fruiting bodies appear all year round, and collecting slippery jacks is one of the main reasons for establishing plantations there.
• Cheap slippery jack powder is sometimes added to the more expensive powder of porcini; the fraud is detected chemically or by DNA methods.
• It is one of the few slippery jacks with a ring and is the type species of the genus Suillus.