Suillus luteus

The genus Suillus

The genus Suillus belongs to the order Boletales, 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 luteus

This fungi is famous for its very slimy cap- hence the common name ‘Slippery Jack’. It is an edible, if not very highly rated, species which is recommended to be picked in dry weather to avoid any excessive slime. However, reports have recorded that some people show allergic reaction to this species.

The cap has a purple-brown or yellowish-brown colouration and varies between 5 and 15 cm in diameter. The tubes are very fine and pale yellow and are attached to the stem which is known as being slightly ‘decurrent’. The stem is rather short and thick varying between 3-6 cm in length and 1-2.5 cm in thickness. Suillus luteus possess a stem ring which is a very nice field characteristic. The flesh is white to yellow being firm and fibrous in the stem and soft and tender in the cap.

Season:

Suillus luteus can be found from late summer to autumn.

Habitat:

Mostly associated with pine.

Distribution:

It is a very common species throughout Scotland.

Similar species

Suillus luteus photos by D. Genney

Suillus luteus 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 f

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