Hebeloma subtortum

The specific epithet subtortum highlights a characteristic Karsten emphasized for this species: its twisted, flexuous stipe.

The presence of a veil and lageniform to ventricose cheilocystidia place it in section Hebeloma. Within this section, based on spore size, it could be confused with H. mesophaeum.

The most reliable microscopic distinction lies in spore shape: more ovoid in subtortum and more ellipsoid in mesophaeum. Macroscopically, subtortum tends to possess a higher number of lamellae and more robust basidiomata. Habitat also provides a clue: while mesophaeum has an Atlantic distribution, subtortum is restricted to Mediterranean climates, typically under Quercus and Pinus.

Specimens examined here were gathered in December in a sandy holm oak wood in Lantarón (Álava).