Leccinum versipelle
Description
Leccinum versipelle is a common edible mushroom in the genus Leccinum. It is found below birches from July through to November and turns black when cooked. Appearing only under birch trees, sometimes together with Leccinum scabrum.
Formerly considered as separate species, following DNA analysis Leccinum cerinum, Leccinum percandidum and Leccinum roseotinctum are now considered by many authorities to be merely color forms of Leccinum versipelle.
Leccinum versipelle is mildly toxic (causing nausea and vomiting) unless given proper heat treatment: frying or boiling for 15–20 minutes is considered necessary. As mentioned, the mushroom turns black when heated.
Common names: Boletus Testaceoscaber, Orange Birch Bolete.
Mushroom Identification
Cap
Mature caps grow from 8 to 20 cm in diameter, remaining broadly convex rather than flattening out completely.
A distinguishing feature of this bolete is the fact that the cuticle overhangs the cap margin by typically 2-4mm. The surface is minutely downy, usually orange or yellowish-brown. As with so many of the Leccinum boletes, there is also a rare pallid form whose cap is almost white, sometimes tinged with pink or orange. Beneath the cuticle, the flesh of the cap is firm and white; it does not change color significantly when a cut or broken surface is exposed to air, but it becomes gradually greyer and eventually blackens with a violet tinge.
Tubes and Pores
The mouse-gray tubes terminate in tiny pores that turn ochraceous with age.
Stem
The stipe or stem, which can be up to 20cm tall and is typically 2 to 4cm in diameter, tapering in slightly towards the apex, has a white, pale grey, or yellowish-gray surface covered with dark brown or blackish woolly scales.
When cut, the pale stem flesh turns gray near the apex but blue-green and then almost black, especially near the stem base.
Spores
Fusiform, thin-walled,11-16 x 3.5-4.5µm, inamyloid.
Spore print
Ochraceous brown.
Cystidia and Basidia
Basidia are four-spored. Cystidia on the fertile tube surface.
Habitat & Ecological role
Mycorrhizal, beneath birch mainly on acidic heathland, woodland edges and scrub.
Similar species
Leccinum scabrum, which also occurs under birch, has a brown cap; its stem flesh does not display a marked color change when it is cut.
History
The Orange Birch Bolete was described in 1835 by Swedish mycologists Elias Magnus Fries and Fredrik Christopher Theodor Hök (1807 - 1877) in their thesis Boleti.
American mycologist Walter Henry Snell (1889 - 1980) transferred this species to the genus Leccinum in 1944, at which point it acquired its currently-accepted scientific name Leccinum versipelle.
Synonyms of Leccinum versipelle include Boletus floccopus Rostk., Boletus testaceoscaber Secr., Boletus versipellis Fr. & Hök, Boletus rufescens Konrad, Boletus percandidus Vassilkov, Leccinum testaceoscabrum Secr. ex Singer, Leccinum percandidum (Vassilkov) Watling, Leccinum atrostipitatum A.H. Sm., Thiers & Watling, Leccinum roseotinctum Watling, Krombholziella roseotincta (Watling) Šutara, Krombholziella rufescens (Konrad) Šutara, Krombholziella versipellis (Fr. & Hök) Bon, Leccinum rufescens (Konrad) Šutara, and Leccinum cerinum M. Korhonen.
Leccinum, the generic name, comes from an old Italian word meaning fungus. The specific epithet versipelle is a reference to the changing nature of the surface of the cap (pellicle).
Although cap color is alluded to in the common names of several Leccinum species, with this group of boletes it is unwise to draw any conclusion from this very variable characteristic.
Photo sources:
Photo 1 - Author: Budyn06 (CC BY-SA 2.5)
Photo 2 - Author: Jörg Hempel (CC BY-SA 3.0)
Photo 3 - Author: Randi Hausken from Bærum, Norway (CC BY-SA 2.0)
Photo 4 - Author: John Fielding (CC BY-SA 2.0)
Photo 5 - Author: Lukas from London, England (CC BY-SA 2.0)
