Hericium erinaceus
A fungus with distinctive white football-sized fruitbodies, formed of clusters of long (10-40 mm), downward-pointing, icicle-like spines, often fruiting high up on exposed central deadwood of old standing Fagus or Quercus trees.
Basidiomata (fruitbody) sessile or short-stemmed, up to 40 cm across, normally comprising one or more large, apiliate (without cap) clusters of long, downward-hanging spines. Context (fruitbody flesh) soft, fleshy, white becoming yellowish brown with age. Hymenophore (hymenium-bearing structure) composed of conspicuous teeth or spines, 10-40 mm long, white becoming sordid yellowish brown. Basidiospores 5-6 x 4-5 µm, broadly ellipsoid, hyaline, strongly amyloid (staining blue to black in iodine-containing solutions), finely but distinctly warted, hilar appendix (attachment peg) inconspicuous. Basidia 25-35 x 6-7 µm, clavate (club-shaped), bearing 4 sterigmata (or “horns”). Hyphal system monomitic (only living “generative hyphae” present); generative hyphae hyaline, mostly strongly amyloid, acyanophilous (cell walls do not readily absorb cotton blue stain), with clamp connections; in the context, most hyphae are highly inflated and very thick walled, often with just a narrow inner space remaining; a few are narrower, thin to thick-walled, 3-12 µm diam., walls up to 8.5 µm thick; narrower in spines, thin to thick walled, 3-12 µm diam., walls up to 1 µm thick. Gloeoplerous elements (highly refractive) abundant and conspicuous in the trama (inner flesh) of the spines, sinuous, often irregularly swollen and pinched, with yellowish, refractive contents, frequently emerging as projecting gloeocystidia in the hymenium.
Description adapted from Pegler, D. N., Roberts, P. J., & Spooner, B. M. (1997). British chanterelles and tooth fungi. Royal Botanic Gardens, Kew.
Not formally assessed in GB&I, but of conservation concern throughout its European range. Unofficially red-listed as Vulnerable in Great Britain in 1992, but later removed from the list in the current but unofficial Red Data List of Threatened British Fungi (Evans et al., 2006).
Designated as a species “of principal importance for the purpose of conserving biodiversity” covered under section 41 (England) and section 42 (Wales) of the NERC Act (2006) and therefore need to be taken into consideration by a public body when performing any of its functions with a view to conserving biodiversity.
Legally protected under Schedule 8 of the Wildlife & Countryside Act 1981.
Superficially similar species include Hericium cirrhatum, which forms one or more distinct pilei or “caps” and possesses much shorter spines (5-15 mm long); and Hericium coralloides, which forms coral-like fruitbodies with much shorter spines (5-10 mm long), and which is typically found on fallen trunks and branches rather than standing tree hosts.
Hericium erinaceus fruits from central deadwood of trunks and large diameter branches of living and dead, standing and fallen, broadleaved trees, most commonly Fagus (beech), but also Quercus (oak). Host trees are typically old pollarded trees, or mature trees with spreading crowns, but fruiting has occasionally been recorded on wounded or damaged younger trees in plantations.
In GB&I, infrequently recorded but widespread across much of south England, with scattered records extending into the Midlands as far north as the Lake District. A few records have also been made on the Welsh side of the England-Wales border. Apparently absent in Scotland or Ireland.