The genus was circumscribed by Finnish mycologist Otto Miettinen in 2016 with Butyrea luteoalba as the type species.
The generic name, derived from the Latin word butyrum ("butter"), refers to the oil-containing cells (gloeocystidia) that are characteristic of the genus.
[1] Butyrea species are poroid with annual, yellowish, crust-like basidiocarps and minute pores numbering 4–8 per millimetre.
The skeletal hyphae are moderately cyanophilous (with cell walls that absorb cotton blue stain), narrow and sinuous, measuring mostly less than 2.5 μm wide with a distinct lumen that is 1/3–1/2 of the width.
The spores of Butyrea fungi are straight and cylindrical with thin walls, and have dimensions of 4–5 by 1.7–2.3 μm.