Leccinum pseudoscabrum (Kallenb.) Šutara - Hazel Bolete

Phylum: Basidiomycota - Class: Agaricomycetes - Order: Boletales - Family: Boletaceae

Leccinum pseudoscabrum, Hazel Bolete

Despite its common name Hazel Bolete, Leccinum pseudoscabrum is most often found beneath Hornbeam trees, although, as the common name implies, it does indeed sometimes occur with Hazel. I see this bolete under hedgerows as well as deep inside woods.

Formerly much better known as Leccinum carpini, this distinctive bolete fruits very early in the year: in Wales I have seen Hazel Boletes as early as the middle of June.

Leccinum pseudoscabrum, west Wales

Distribution

Widspread but far from common in Britain and Ireland, Leccinum pseudoscabrum is also found in many parts of northern and central Europe.

Taxonomic history

The basionym of this species dates from a 1935 publication by German mycologist Franz Joseph Kallenbach (1893 - 1944), who gave it the scientific name Boletus pseudoscaber. It was Czech mycologist Josef Šutara (b. 1943) who, in 1989, established the currently-accepted scientific name Leccinum pseudoscabrum.

Synonyms of Leccinum pseudoscabrum include Boletus scaber var. carpini R. Schulz, Boletus pseudoscaber Kallenb., Boletus carpini (R. Schulz) A. Pearson, Leccinum carpini (R. Schulz) M.M. Moser ex D.A. Reid, and Krombholziella pseudoscabra (Kallenb.) Šutara.

Etymology

Leccinum, the generic name, is derived from an old Italian word meaning fungus. The specific epithet pseudoscabrumcomprises the prefix pseudo- meaning almost or similar to, and the suffix -scabrum meaning with scabers - a reference to the roughly scaly or scurfy surface of stems of this mushroom.

Identification guide

Cap of Leccinum pseudoscabrum

Cap

Smaller than many Leccinum mushrooms, the cap diameter ranges between 4 and 9cm in diameter when fully expanded, remaining broadly convex rather than flattening out completely. The surface is usually wrinkled and sometimes cracked. When moist the cap surface is tacky or slightly greasy, drying to dull matt or very finely fleecy.

Cap colour ranges from yellowish-brown to olive-buff or olive-brown. The cap flesh turns vinaceous when cut and exposed to air.

Pores of Leccinum pseudoscabrum

Tubes and Pores

The creamy-white tubes terminate in pores typically 0.5mm in diameter that are also creamy white. The pores turn slowly blackish when they are bruised.

Closeup of stem of Leccinum pseudoscabrum

Stem

The stipe or stem is 4-12cm tall and typically 0.8 to 1.2cm in diameter, tapering in slightly towards the apex, has a white or pale grey surface covered with buff scales near the apex grading o brown scales near to the stem base.

When cut, the pale stem flesh turns vinaceous near the apex and blueish towards th stem base.

Spores of Leccinum pseudoscabrum

Spores

Fusiform with a conical apex, smooth, thin-walled,13-18.5 x 4-6µm, inamyloid.

Spore print

Ochraceous-brown.

Note: Other microscopic characters may have to be examined before a specimen can be conclusively recorded as Leccinum pseudoscabrum . Of particular significance are the caulocystidia and the hyphal structure of the pileipellis. See the key by Geoffrey Kibby, in the References section below.

Odour/taste

Not distinctive.

Habitat & Ecological role

Mycorrhizal, most often beneath hornbeam but less commonly with hazel.

Season

June to October in Britain and Ireland.

Similar species

Leccinum scabrum, a larger bolete which usually occurs under birch, generally has a browner cap but is occasionally yellowish brown.

Culinary Notes

Leccinum pseudoscabrum is generally considered to be an edible mushroom, but it is not in the first division of boletes and its small size and relative scarcity make it hardly worth seeking if you are looking for mushrooms to eat.

Reference Sources

Pat O'Reilly, Fascinated by Fungi, 2016.

Henk C. den Bakker, Barbara Gravendeel & Thomas W. Kuyper (2004). An ITS phylogeny of Leccinum and an analysis of the evolution of minisatellite-like sequences within ITS1; Mycologia, 96(1), 2004, pp. 102-118.

British Boletes, with keys to species, Geoffrey Kibby (self published) 3rd Edition 2012.

British Mycological Society English Names for Fungi

Dictionary of the Fungi; Paul M. Kirk, Paul F. Cannon, David W. Minter and J. A. Stalpers; CABI, 2008

Taxonomic history and synonym information on these pages is drawn from many sources but in particular from the British Mycological Society's GB Checklist of Fungi and (for basidiomycetes) on Kew's Checklist of the British & Irish Basidiomycota.

Other web pages on this species

Machiel Noordeloos (Netherlands)

Roger Phillips (UK) - under pseudonym Leccinum carpini

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