Suillus granulatus

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 granulatus

Suillus granulatus has, as most of its genus colleagues, a slimy cup in wet weather but has shinny and dry appearance in dry conditions. The cap colour is somewhere in between Suillus luteus and Suillus grevillei and is between 4-10 cm in size. The pores are whitish yellow and release milky droplets which give it its common name ‘Weeping Bolete’. The stem is 4-10 cm in length, 1-2 cm thick and does not possess a ring – a feature which makes it more easily distinguishable from Suillus luteus. Instead, it is covered completely or just the upper half with yellowish granulates which are formed as milky droplets released from the stem that turn hard and dark. The flesh is yellow and firm at first but later turns soft and watery.

This edible species has a nutty taste which makes it a more favourable species for collecting. It is a common species throughout Scotland, which between June and November and is therefore one of the first Suillus species throughout the year.

Season:

Suillus granulatus can be found between June and November and is therefore one of the first Suillus species throughout the year.

Habitat:

Often grows in troops under coniferous trees

Distribution:

It one of the least common species of Suillus throughout Scotland

Similar species

Suillus granulatus photos by D. Genney

Suillus granulatus 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. granulatus. 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