Suillus bovinus

The genus Suillus

The genus Suillus belongs to the order Boletales and has distinctive features that are shared by many of the different Suillus species. These middle-sized fungi have a firm, cylindrical stem that often has a ring resulting from the remains from the partial vail (the membrane that protects the spore producing pores under the cap as the mushroom develops). The caps of most species are slimy or slippery, especially after rain, and have pore like structures on the underside which range in colour from yellow, light orange to olive green or even grey shades. The spore colour of this genus is usually cinnamon brown to chocolate brown. The name ‘Suillus’ comes from the Latin noun sus meaning pig. Hence, Suillus means ‘of pigs’ and refers to its greasy cap which is shared by the different Suillus species.

Suillus bovinus

Jersey Jack is another common representative of the genus Suillus – and unsurprisingly got its common name as it is said to have the same cap colour as the Jersey Cow. The cap skin is ochre brown and shiny when moist but dries quickly otherwise giving it a less shiny appearance. Younger specimens have cushioned shaped caps with a slightly in-rolled white margin. With age this feature disappears and the cap becomes irregularly flattened varying between 3-10 cm in size. The best field characteristic for these species is the pores within pores, also known as ‘compound pores’. The stem, has a similar colour as the cap and varies between 3-6 cm in length and 0.5-1.5 cm in thickness. Suillus bovinus does not have a ring, the stem is almost always saffron yellow at the top and is commonly covered with fibres. The flesh is pale yellow and tends to turn pinkish with age.

Suillus bovinus prefers poor, acid soils within coniferous woodlands and can often be found together with Gomphidus roseus which is thought to be a parasitic fungus. Jersey Jack has a pleasant fruity smell and as the other described species is an edible fungi with low culinary interest.

Season:

Suillus bovinus can be found from late summer to autumn.

Habitat:

Associated with conifers.

Distribution:

It is a very common species throughout Scotland and can sometimes form almost continuous lines of fruitbodies along the edges of forestry tracks.

Similar species

Suillus bovinus with the red capped associate Gomphidus roseus (by P. Ehrlich)

Suillus bovinus photos by D. Genney

Suillus bovinus distribution map

The National Biodiversity Network Gateway records from FRDBI andHBRG datasets are shown on the above map but note that more recent records may be available via the Gateway (see terms and conditions at http://data.nbn.org.uk). Data providers and the NBN Trust bear no responsibility for any further analysis or interpretation of the information in the map.

Note also that additional records may be available on the Association of British Fungus Groups CATE2 database, but these are not available via the NBN Gateway.

The other species of Suillus are relatively easy to differentiate from S. luteus. See their profiles in the

Fungus of the Month index page.

There are two other main groups of fungi that have a central stem and pores instead of gills:

Boletus species have dry caps and normally a network pattern on stem e.g. Cep.

Leccinum species have stems that are covered in small scales of varying colours, dry caps and associated with broadleaf trees e.g. Orange Birch Bolete.

Please remember to submit your records to your local recording group or via the Scottish Fungi online recording form.

By Peggy Ehrlich and Dave Genney

September 2016