Agrocybe rivulosa

Cap: 6.5 cm Cream/beige colour, dark cracking with age
Gills: Adnate, crowded, pale grey/beige when young turning brown with age
Spores: brown, 12 x 6.8 um
Veil: present on young specimen, tearing with age and leaving veil remnants on stem as ring
Stem: 7.5 x 1-2 cm (widening at base), stem snapped cleanly and hollow. Rhizomorphic mycelium at base.
Habitat: wood chip