It was created in 1987 to contain species formerly placed in genus Parmelina that had a yellow-orange medulla due to the presence of secalonic acids.

Characteristics of the genus include tightly attached thalli with narrow lobes, cilia on the axils, and a rhizinate black lower surface.

Myelochroa was originally circumscribed by Yasuhiko Asahina as a subsection of section Hypotrachyna in genus Parmelia.

The upper surface of the thallus is grey, or blue-grey, sometimes with a yellow tinge; this yellowish colour, if present, is more likely to be under the apothecia or close to the algal layer.

The presence of these triterpenes distinguishes this genus from Parmelina, and its segregate genera, including Parmelinella, and Parmelinopsis.

[3] The taxon once known as Myelochroa lindmanii (Lynge) Elix & Hale (1987) has been analysed molecularly and shown to belong to the genus Parmelinella.