This species is recognized by the bitter taste of the cap cuticle. The cap colour varies from pale greyish white to pale yellow, the gills are pale greyish white - sometimes with a violaceous tinge. It has small, almost smooth spores.

C. caesiostramineus is mainly associated with spruce (Picea) and pine (Pinus), but sometimes also with beech ( Fagus) or oak (Quercus). This collection was made in a coniferous forest on calcareous soil.