| Suillus | |
|---|---|
 | |
| Suillus luteus | |
Scientific classification | |
| Kingdom: | Fungi |
| Division: | Basidiomycota |
| Class: | Agaricomycetes |
| Order: | Boletales |
| Family: | Suillaceae |
| Genus: | Suillus Gray (1821) |
| Type species | |
| Suillus luteus (L.) Roussel (1821) | |
| Synonyms[1] | |
| |
Suillus is agenus ofbasidiomycete fungi in the familySuillaceae and orderBoletales. Species in the genus are associated with trees in the pine family (Pinaceae), and are mostly distributed intemperate locations in the Northern Hemisphere, although some species have beenintroduced to theSouthern Hemisphere.[2]
The genusSuillus was first defined byPier Antonio Micheli in his 1729 workNova plantarum genera, however it is not valid as it predates the 1753 start of Linnean taxonomy.[3] Fries sanctioned the use by British botanistSamuel Frederick Gray in the first volume of his 1821 workA Natural Arrangement of British Plants. SettingSuillus luteus as thetype species, he described the genus as those mushrooms with a centrally placed stipe, a distinctring, a circular cap, and tubes that are stuck together.[4]
They have been commonly called "slippery jacks" because the cap of thefruit body is sometimes slimy. The genus name is derived from theLatinsus, meaning "pig". Before 1997, the genusSuillus was considered part of the familyBoletaceae.
The genus also contains what were known as the larch boletes, several species that were described in the genusFuscoboletinus. These grow in association with larch or tamarack (Larix ssp.). Molecular analysis has shown them to not be a monophyletic group and to be mixed in with theSuillus species.[a]
Structures of the fungi in this genus in common with other members of the orderBoletales include the presence of a cylindricalstipe,cap, softflesh and tubularhymenium. Specific characteristics common to most species inSuillus are thecap cuticle which is often slimy and sticky when moist, the presence of darkly staining, clustered, sterile cells calledcystidia that give the tube mouths or the stipe surface a speckled or glandular appearance, spores that are usually cinnamon brown or chocolate brown in mass, and obligatemycorrhizal relationships primarily with members of thePinaceae, especially with members of the generaPinus,Larix andPseudotsuga.
Intra-genus variation may be demonstrated by differences in colour and ornamentation of the cap cuticle, flesh, pores and stipe, the presence of apartial veil in immature forms andannuli thereafter, pore shape and distribution, as well as habitat. The cap cuticle is dark brown inS. brevipes, and yellow inS. grevillei.S. granulatus has a smooth cap cuticle, while that ofS. lakei is finely scaly. The pores are bright yellow inS. collinitus, cinnamon inS. variegatus and grey inS. viscidus; in shape they are round inS. luteus and angular inS. bovinus. The flesh is white to yellow inS. luteus, while it is pallid inS. variegatus with a tendency to turn blue when exposed to air. YoungS. luteus andS. grevillei bear partial veils whose remnants remain as annuli hanging from the stipe; inS. granulatus the stipe is bare.S. viscidus andS. grevillei occur underlarch (Larix) only, whileS. sibiricus is restricted to a few species of 5-needled pine (Pinus).
Species ofSuillus are found all over theNorthern Hemisphere where members of the tree familyPinaceae can be found. Although a few species are distributed in tropical regions (usually mountainous areas), most are limited totemperate areas. Some species have beenintroduced adventitiously with pine trees in pineplantations outside the natural area of Pinaceae.[6]
SomeSuillus species have entered regionalred lists as endangered or vulnerable. Seven European countries have listedS. sibiricus.[7] Individual countries have also listed other species, includingS. flavidus,S. tridentinus,S. collinitus,S. plorans andS. lakei.[8]
SomeSuillus species areedible and are highly esteemed, particularly inSlavic countries, where they are generally referred to as butter mushrooms (маслята). They are generally picked as buttons when the flesh is still firm. In some species, the slimy cap coat acts as apurgative when consumed and should be removed before cooking. Species ofSuillus have been associated with the term "bolete", given to members of other genera bearing pores, most notablyBoletus.
Some species can be used to makemushroom dyes, likeS. americanus,S. cothurnatus,S. granulatus,[9] andS. luteus.[10]
A 2025 study aiming to characterize thesubgenera,sections, and new species ofSuillus, based on molecular data combined withmorphology and ecology, recognized 12 new species, 5 new location records, and 14 potentially new species revealed inEast Asia.[11]
As of November 2025[update],Index Fungorum andCatalogue of Life list 126 valid species ofSuillus, some of which are listed below:[12]
