Hericium coralloides
A distinctive and attractive fungus with a conspicuous white (when young), branched, coral-like fruitbody, up to 25 cm across; with each branchlet producing downward-pointing spines or "teeth" 5-10 mm in length; growing on fallen trunks and large logs of Fagus sylvatica (common beech), and less commonly Fraxinus excelsior (common ash), and Ulmus (elm).
Basidiomata (fruitbody) up to 25 cm across, apileate (without cap), branching extensively from a basal or lateral stipe (stem) to produce coral-like outgrowths of branchlets and spines. Context (fruitbody “flesh”) soft, white to pinkish, becoming beige to yellowish brown with age. Hymenophore (hymenium-bearing structure) of conspicuous downwards-hanging spines or teats, 5-10 mm long. Basidia 15-35 x 3.5 µm, bearing 4 sterigmata ("spikes" or "horns"). Basidiospores 3.5-5 x 3-4 µm, broadly ellipsoid, hyaline, strongly amyloid (staining blue to black in iodine-containing solutions), finely punctate (studded with dots or holes) (at least when mounted in lactophenol cotton blue), hilar appendage (attachment peg on basidiospore) inconspicuous. Hyphal system monomitic (only living "generative" hyphae present), generative hyphae hyaline, varying within a single fruitbody from inamyloid to weakly or strongly amyloid, acyanophilous (cell walls do not readily absorb cotton blue stain), with clamp connections; in the stipe context, most hyphae are inflated and thick-walled, some narrower and thin-walled, 3-25 µm diam., with walls up to 3.5 µm thick; most hyphae in spines narrower, 1.5-12 µm diam., some with slightly thickened refractive walls up to 1 µm diam. Gloeoplerous elements (highly refractive) present and conspicuous in the trama (inner flesh) of the spines, sinuous, often irregularly swollen and pinched at intervals, with yellowish, refractive contents, frequently emerging as gloecystidia 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. Considered Near Threatened in the current but unofficial Red Data List of Threatened British Fungi (Evans et al., 2006).
Designated a species “of principal importance for the purpose of conserving biodiversity” covered under section 41 (England) of the Natural Environment and Rural Communities (NERC) Act 2006, and therefore needs to be taken into consideration by a public body when performing any of its functions with a view to conserving biodiversity.
Superficially similar species include Hericium cirrhatum, which forms one or more distinct pilei or “caps”; and Hericium erinaceus, which lacks the coral-like branching of H. coralloides and has much longer spines (10-40 mm vs 5-10 mm in H. coralloides).
In GB&I, the large majority of recorded fruitbodies were observed on Fagus sylvatica (common beech), typically on fallen trunks or branches, with the remainder being on Fraxinus excelsior (common ash), and a single record from Ulmus (elm).
In GB&I, infrequently recorded but with sites widely distributed throughout south and east England, with scattered records in the Midlands and Yorkshire. Recorded once in Wales, from Monmouthshire VC38. Not recorded in the wild in Scotland.