Bovine Bolete

Description

The bovine bolete is a small pored mushroom with a sticky, cream-ochre to orange-brown cap 4–12 cm across. Underneath the cap it has very large, angular pores resembling the holes of a sieve, which run down the stem. The stem is slender, without a ring. The flesh is elastic, rubbery and smells slightly fruity.

It grows from July to October on dry, sandy soils under pines, often among heather. In Poland it is the most common slippery jack.

It is distinguished from the velvet bolete by its larger pores and lack of bluing; it is harder to peel, because the cuticle is sticky and clings firmly. When cooked it turns red-violet, which puts off some mushroom pickers. If you are not sure of the species, do not pick it and do not eat it.

Identification features

Cap

Diameter 3–12 cm (descriptions give different ranges). At first hemispherical with a slightly wavy margin, later flat, bent in older ones. Cuticle with a delicate, pale, felty bloom when young, then sticky (slimy when wet), shiny, smooth, very hard to peel. Colour cream, cream-ochre, orange-ochre, orange-brown (according to some descriptions grey-yellow or ochre, sometimes with a pink tinge), usually with a paler rim at the margin.

Hymenophore (underside of the cap)

Tubes 3–10 mm long (descriptions give different ranges), attached to the stem, often running down. Young ones grey-yellowish, then yellow, grey-ochre, finally brownish (according to some descriptions yellow to olive-yellow). Pores very large, angular, resembling the holes of a sieve; the pore layer is compound: the outer layer of coarser pores lies over the inner layer of finer ones. They separate from the flesh of the cap with difficulty. Turn brown when pressed.

Stem

Height 2–10 cm, thickness 0.5–2 cm (descriptions give different ranges); cylindrical, solid, fibrous, without a ring, more slender than in other slippery jacks. Colour of the cap or slightly paler, sometimes red-brown at the base. The mycelium at the base of the stem whitish to violet-pink.

Flesh

Elastic, rubbery, cream, ochre-orange to brownish, sometimes pink or reddish in the stem. Does not change colour when cut (according to some descriptions sometimes pinkish when damaged), usually pink-reddish after drying. Smell delicate, pleasant, slightly fruity; taste mild, slightly sour. Turns red-violet when cooked.

Spore print and spores

Spore print yellow-olive to olive-brown. Spores smooth, spindle-elliptical, 6.5–11 × 3–4.5 µm (descriptions give different ranges).

Habitat and distribution

Ecology. Mycorrhizal fungus, in Poland associated with Scots pine; in other countries also with other pines. Grows on dry, sandy, acidic (sometimes calcareous) soils, often among heather. More abundant in younger forests and on disturbed sites; colonies do not overlap, and their median life span is about 36 years. It is sometimes parasitised by the rosy spike-cap (Gomphidius roseus), which grows exclusively with it. Shows some saprotrophic activity.

Distribution. Northern Hemisphere; in the Southern Hemisphere only in New Zealand (according to some descriptions also in Australia and South Africa, as an introduced species). Common in Poland, the most frequent of all slippery jacks. In the Alps up to about 800 m. Not legally protected in Poland.

Fruiting. From July to October.

What can it be confused with?

• Suillus variegatus (velvet bolete; sometimes called the granulated bolete) — Smaller pores (dark olive, not running down the stem), upper part of the stem dotted with spots; cap granular, may turn blue.
• Suillus flavidus (Polish: maślak błotny) — Very rare; has a ring on the stem and coarse, embedded fibres on the cap. Protected in Poland (partial protection), not included in the Atlas — do not pick.
• Gyrodon lividus (alder bolete) — Thin tubes run far down the stem and are strongly fused with the flesh of the cap.
• 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.

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

• The species name comes from Latin bos (cattle); in English the mushroom is called the Jersey cow mushroom because of its colour.
• It is the type species of the genus Suillus; one of the species described by Linnaeus in 1753.
• The fruiting bodies are part of the squirrel's late-summer diet; the squirrel collects them and stores them in forks of trees.
• A single colony can live for several decades; in mature forests a single colony reaches up to a dozen or so metres across.