What You Should Know
Gyroporus cyanescens is a species of bolete fungus in the family Gyroporaceae. First described from France in 1788, the species is found in Asia, Australia, Europe, and eastern North America, where it grows on the ground in coniferous and mixed forests.
All parts of the mushroom turn an intense blue color within a few moments of bruising or cutting. The mushroom is edible, despite its hard stem. A less common variety occurs where the color change is to deep violet rather than blue. The bluing reaction results from the oxidation of a chemical called gyrocyanin.
Other names: Cornflower Bolete, Bluing Bolete.
Gyroporus cyanescens Mushroom Identification
Often reported as mycorrhizal with hardwoods, but, as Singer (1945) notes, it grows in woods and even on meadows and does not seem regularly to form mycorrhiza, at least no preference of any forest tree is shown, and sometimes fruiting bodies are formed far from any tree at all; growing alone, scattered, or gregariously, usually in sandy soil, especially in the disturbed ground (roadbeds, path sides, and so on); summer and fall; fairly widely distributed east of the Rocky Mountains.
4-12 cm; convex, becoming broadly convex or, sometimes, nearly flat in age; dry; coarsely roughened or, sometimes, matted-scaly and hairy; straw-colored or paler; bruising quickly blue.
White to yellowish; bruising immediately blue; 1-3 round pores per mm; tubes to 18 mm deep.
4-12 cm long; 1-3 cm thick; more or less equal, or swollen; brittle; soon hollowing; colored like the cap or slightly paler; not reticulate; textured like the cap, or nearly bald in age; bruising quickly blue.
White to pale yellow; brittle; bruising blue on exposure.
Spore Print: Pale yellow.
Gyroporus cyanescens Taxonomy and Etymology
This bolete was named and described in 1788 by French botanist and mycologist Jean Baptiste François Pierre Bulliard, who gave it the binomial scientific name Boletus cyanescens. It was another French mycologist, Lucien Quélet, who transferred this mushroom to its present genus, which he himself established in 1886.
Synonyms of Gyroporus cyanescens include Boletus cyanescens Bull., Boletus constrictus Pers., Leccinum constrictum (Pers.) Gray, Boletus lacteus Lév., and Gyroporus lacteus (Lév.) Quél.
The generic name Gyroporus comes from the Greek Gýros, meaning round, and porus, an opening - hence round pores; while the specific epithet cyanescens means 'becoming blue'.
Like other boletes, Gyroporus cyanescens is an ectomycorrhizal fungus, which means that it forms symbiotic relationships with the root systems of trees. In the case of the Cornflower Bolete it has been found to associate with various conifers including pines and spruces as well as with some hardwoods such as birch and oak trees.
Photo 1 - Author: Luke Smithson (Creative Commons Attribution-Share Alike 4.0 International)
Photo 2 - Author: Andreas Kunze (Creative Commons Attribution-Share Alike 3.0 Unported)
Photo 3 - Author: Luke Smithson (Creative Commons Attribution-Share Alike 4.0 International)
Photo 4 - Author: Christian Grenier (Public Domain)
Photo 5 - Author: Christian Grenier (Public Domain)