Notulae ad Floram agaricinam neerlandicam — XXXIX. Bolbitius

A key is provided to the European taxa of Bolbitius, mainly based on a revision of material from the Netherlands and adjacent regions. The nomenclature and morphological variation of B. titubans and B. reticulatus are discussed. The new combination B. titubans var. olivaceus is proposed. Full descriptions are given of the critical species B. demangei and B. lacteus. Bolbitius ferrugineus is described as a new species, based on material from southern Italy.