Notulae ad Floram agaricinam neerlandicam — XXXIII. Notes on Agaricus section Spissicaules

The subsection Spissicaules of Agaricus section Sanguinolenti is raised to section level. It is mainly characterised by the simple annulus, the presence of yellowing rhizomorphs, yellow discolouration of the context or surface at the base of the stipe and a positive Schaeffer-reaction, and the slightly reddening context in the higher part of the stipe. Section Spissicaules comprises three species in the Netherlands, viz. Agaricus lanipes, A. litoralis, and A. bresadolanus. Both. A. maskae and A. spissicaulis are considered synonymous with A. litoralis; A. romagnesii is regarded as conspecific with A. bresadolanus. A new species is described from the Netherlands and Great Britain, A. rufotegulis, which is tentatively placed in subgenus Lanagaricus on account of the covering of the pileus and stipe.