Hohenbuehelia bonii  

An almost sessile (barely stalked), yellow-brown oyster mushroom with fruitbodies up to 6 or 7 cm diam., growing on bases of Ammophilia, in mobile dunes facing the sea, or sometimes in further back more fixed (grey dune) vegetation. Fruitbodies have been recorded from September to January in GB.

H. bonii was treated in GB as Hohenbuehelia culmicola until 2016, but is now recognised as a distinct species with the same or very similar habitat preference as H. culmicola s.s. Both species are present in GB and co-occur in at least some sites.

Pileus 20–75 mm diam., fan-shaped, pleurotoid, semi-infundibuliform or spathulate with incurved margin, applanate becoming irregularly lobed, yellow-brown to sepia, often paler near the margin, with gelatinous texture and central zone of sparse pale tomentum, particularly prominent towards the stipe apex. Lamellae crowded, forked, strongly decurrent, white or cream-ochraceous. Stipe concolorous with lamellae or darker tan, to 15 x 20 mm, usually short and stout, laterally attached, flattened, widest at the apex, usually basally encrusted with sand and sometimes with attached white mycelial cords. Spores (from prints, measured in water) 7.2–10.4 x (3.6)4.5–6.1 µm, per-basidioma mean values 8.2–8.7 x 5.0–5.5 µm, Q = 1.3–2.0, mean 1.6, ellipsoidal, white, no Melzer’s reaction. Mature basidia predominantly 4-spored in most collections (2-spored in K(M)102858, North Bull Island, fide Elborne’s annotation in K), clavate, 22–48 x 5–9 µm excluding sterigmatal length (4.0–9.5 µm), spores within tetrad sometimes showing asynchronous development. Clamp connections at basidial bases and on all other hyphae. Metuloid pleuro-cystidia fusoid, variably apically encrusted, 56–103 x 11–19 µm with wall thick-ness 1.6–8 µm, sometimes with occluded lumen. Dense array of ‘gloeosphex’ thin-walled cheilocystidia and rare pleurocystidia cylindrical or lageniform with rostrate toruloid apex, often with mucoid droplet enhancing capitate aspect, sometimes branched with 2–3 capitate apices, 32–53 x 3.2–9.6 µm with apical width 3.2–6.4 µm. Pileipellis an ixotrichoderm or ixocutis, bearing patches of slender, variably encrusted pileometuloids 64–104 x 3.6–6.1 µm with wall thickness ca. 1.5 µm, surmounted by a dry trichoderm (pileal tomentum) in central zone near stipe attachment.

Description adapted from Ainsworth, A. M., Suz, L. M., & Dentinger, B. T. (2016). Hohenbuehelia bonii sp. nov. and H. culmicola: two pearls within the Marram Oyster. Field Mycology, 17(3), 78-86.

Map of known distribution in Great Britain and Ireland.