Leccinum cyaneobasileucum
Description
Leccinum cyaneobasileucum is a species of bolete fungus in the family Boletaceae. Originally found growing under silver birch. The fungus produces fruit bodies with caps measuring 5–15 cm (2–6 in) wide that range in color from hazel to reddish-yellow, to walnut brown. The white to grey stipe measures 7–20 cm (3–8 in) long by 0.8–2 cm (0.3–0.8 in) thick and is covered with brownish scales. In deposit the spores are walnut brown; microscopically, they are somewhat spindle-shaped and measure 14–18 by 5–6 µm. L. cyaneobasileucum grows under birch, usually in moss. The mushroom is edible but not particularly tasty.
Common names: Greyshank Bolete.
Mushroom Identification
Cap
Various shades of gray-brown (and there is a very rare albino form), the cap of Leccinum cyaneobasileucum is usually circular and only occasionally slightly misshapen with its margin somewhat wavy (but rarely as irregular as many large specimens of its lookalike Leccinum scabrum).
The cap surface is very finely tomentose (like velvet), and the margin of the pellicle overhangs the tubes very slightly in young fruitbodies. Initially, hemispherical, caps, which become convex but do not flatten completely, range from 4 to 8cm in diameter when fully developed.
Tubes
The circular tubes, typically 0.5mm in diameter, are broadly adnate to the stem; they are 1 to 1.5cm long, off-white with a gray-brown tinge.
Pores
The tubes terminate in pores that are similarly colored. When bruised, the pores do not undergo a rapid color change but gradually turn slightly browner.
Stem
Very pale grey to grayish brown and covered with concolorous scales that turn greyer with age, the stems of Leccinum cyaneobasileucum range from 1 to 2.5cm in diameter and are usually 7 to 14cm tall.
Immature specimens often have barrel-shaped stems; at maturity stems become more regular in diameter, usually slightly clavate and tapering in towards the apex.
The stem flesh is white but sometimes turns slightly pink near the apex when it is cut or broken and always blues (although often only in a very limited region) at the base. The exterior of the stem base usually has a blue tinge that is most noticeable where slugs, snails, or bugs have damaged its surface - a helpful identifying feature.
Basidia
Mainly 4-spored but usually with some 2-spored basidia.
Spores
Fusiform, 13-19 x 4-6.5 µm.
Spore Print
Pale brown.
Pileipellis
The pileipellis (cap cuticle) usually has numerous cylindrocysts (short, disarticulating hyphal cells, as seen on the left).
Odor and Taste
The faint smell and taste are pleasant but not particularly distinctive.
Habitat & Ecological Role
All Leccinum species are ectomycorrhizal, and most are found only with one tree genus. Leccinum cyaneobasileucum is mycorrhizal only with birch trees (Betula spp.) and in Britain and Ireland, this mushroom is found nearly always beneath Silver Birch Betula pendula or Downy Birch Betula pubescens.
Look-Alikes
-
Does not blue in the stem base when cut or broken; it is often rather larger than Leccinum cyaneobasileucum and there are significant differences in microscopic characters that separate these two superficially very similar boletes.
-
Has a much more orange cap and it bruises blue-green in the stem base.
History
The white form of this bolete was described in 1991 by Lannoy & Estadès before they recorded brown form, and because initially they gave the white form the specific name Leccinum cyaneobasileucum, under the rules of the international naming convention the binomial scientific name Leccinum cyaneobasileucum takes precedence
Leccinum brunneogriseolum Lannoy & Estadès, and Leccinum brunneogriseolum f. chlorinum Lannoy & Estadès are Synonyms of Leccinum cyaneobasileucum.
Leccinum, the generic name, comes from an old Italian word meaning fungus. The specific epithet cyaneobasileucum is a reference to the bluing at the stem base when it is cut through or otherwise damaged.
Photo sources:
Photo 1 - Author: Jerzy Opioła (CC BY-SA 3.0)
Photo 2 - Author: Holger Krisp (CC BY 3.0)
Photo 3 - Author: Ron Pastorino (Ronpast) (CC BY-SA 3.0)
Photo 4 - Author: Ron Pastorino (Ronpast) (CC BY-SA 3.0)
