Siderophilous granules in the basidia of Hymenomycetes

Siderophilous granules of postmeiotic basidia are protein filled vesicles derived from the endoplasmic reticulum capable of binding relative large amounts of metal ions thus standing out with high opacity in the electron microscope and becoming stainable with acetocarmine or hematoxylin for light microscopy. They range from very small, submicroscopic, single and rare particles to easily observable granules almost filling the basidium. The number and size of the granules can be used to describe five types of granulation, the crypto, micro, oligo, macro, and gigas type. The macrotype is taxonomically important for the Lyophylleae, and it seems that the micro type has taxonomic significance in the Rhodophyllaceae (Entolomataceae) and the Russulaceae.