On the basis of all accessible records from the literature and our own field observations and collections, the ecology of the rare
myxomycete Barbeyella minutissima is described. Analysis of these data, derived mainly from the Northern Ammergauer Alps
(Germany) and the Appalachian Mountains (USA: West Virginia, North Carolina), permit the microhabitat requirements of this
myxomycete and its ecological associations with other myxomycetes and bryophytes to be elucidated in some detail. Barbeyella
minutissima appears to have a distribution centred in montane spruce-fir forests, where it is regularly associated with three other
species of myxomycetes – Colloderma oculatum, Lamproderma columbinum, and Lepidoderma tigrinum. Several leafy liverworts are
associated with Barbeyella. Particularly noteworthy is Nowellia curvifolia, which seems to be an indicator organism for this
myxomycete. A world distribution map of Barbeyella minutissima is provided, along with conclusions relating to the putative range
of the species.