The collection of fungi, mainly members of the Glomeromycota, consists of voucher specimens and records relating to some three decades of research into the taxonomy and systematics of arbuscular mycorrhizal fungi . Most of the specimens are held in the herbarium at the Royal Botanic Garden Edinburgh (E), though more recent ones may still be retained personally by Chris Walker pending their deposit in the herbarium. The vouchers mainly consist of spores mounted in polyvinyl-alcohol lactophenol (PVL) or polyvinyl-alcohol lacto glycerol (PVLG), with or without the addition of reagents (principally Melzer's reagent) and dyes (e.g., trypan blue, ink). The organisms have been collected by many different people too numerous to mention, and their contributionis acknowledged with thanks. Some are of importance because they are type specimens, and some are voucher records for published work. Some records of types are virtual, being merely pointers to the specimens held in other herbaria.