Suillus grevillei<u>,</u> commonly known as tamarack jack, Greville's bolete, or larch bolete, is a mycorrhizal mushroom with a tight, brilliantly coloured cap, shiny and wet looking with its mucous slime layer. The hymenium easily separates from the flesh of the cap, with a central stalk that is quite slender. The species has a ring or a tight-fitting annular zone.
The specific epithet is derived from Robert Kaye Greville.
Suillus grevillei is a mushroom with a 5–10 cm (2–4 in) cap colored from citrus yellow to burnt orange, that is at first hemispherical, then bell-shaped, and finally flattened. It has a sticky skin, often with veil remnants on the edge, short tubes of yellow (possibly staining brownish) which descend down to the bottom of its cylindrical stalk (6–10 x 1âÂÂ2 cm), which is yellowish above the ring area with streaks of reddish brown below. The flesh is yellow, staining brown.
Taste mild to slightly astringent to bitterish; odor none to somewhat metallic.
It grows only under larch trees. Widespread in North America and Europe (JulyâÂÂNovember). In Asia, it has been recorded from Taiwan.
Suillus grevillei can be cooked as an edible mushroom, though one without culinary interest, if the slimy cuticle is removed from the cap.
The fungus produces grevillin which is characteristic of this fungus. Contain at least 11 yellow, orange and red pigments derived from decarboxylated pulvinic acids, of which 3',4',4- trihydroxypulvinone is the major pigment. Cyclovariegatin is also partly responsible for its colour.
The genetic and enzymatic basis for atromentin, the precursor to various pulvinic acid-type pigments, has been characterized (an atromentin synthetase by the name, GreA). A cosmid library (31âÂÂ249 bp in total) has been made from the genome. The estimated gene density based on the cosmid library is 1 per 3900 bp of genomic DNA. The genome has a GC content of 49.8%.