Agrocybe_cylindracea

Description: Medium to large agaric, in clusters, on wood (Populus alba).

Pileus: Broadly convex, brownish with paler margin when young becoming paler with age as the cap expands but darkening to a dull brown as the cap ages, dry, smooth without striations, diameter 20-80mm (a small population, CS96, had diameters up to 200mm).
Stipe: Whitish to pale brown darkening slightly with age, fleshy, generally tough, straight, with white ring dusted brown with spores which may be lost in old specimens; diameter 3-14mm, 50-130mm height (CS96 26-34mm x 210mm).
Gills: Adnate with decurrent tooth, close, pale coloured changing to tobacco brown on maturity.
Spore print: Tobacco brown.

Microscopy:
Pileipellis: Cellular, with elongated to papillate pileocystidia.
Basidia: 2-, 3- and more commonly 4-spored .
Cheilocystidia: Present, clavate.
Pleurocystidia: Present, variable in shape from clavate to papillate.
Gill Trama: Parallel.
Clamp connections: Present
Spores: Brown, ellipsoid, without a visible germ pore, smooth; L= 7.3-10.4µm, W = 5.0-6.1µm, Q=1.46-1.86, Qm=1.67