Key to the species of Korean Myelochroa 1. Thallus isidiate∙∙∙∙∙∙ M. perisidians (Nyl.) Elix & Hale 1. Thallus without isidia ∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙ 2 2. Thallus sorediate or pustulate ∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙ 3 2. Thallus without soredia or pustules∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙ 6 3. Pustules never forming soredia ∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙ 4 3. Pustules turning into soredia; soredia farinose∙∙∙∙∙∙∙∙∙ 5 4. Medulla P+ brick red, containing galbinic acid; moniliform cells present in the medulla∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙ ∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙ M. hayachinensis (Kurok.) Elix & Hale 4. Medulla P -, lacking galbinic acid; moniliform cells absent in the medulla ∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙ ∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙ M. leucotyliza (Nyl.) Elix & Hale 5. Medulla P+ brick red, containing galbinic acid; moniliform cells present in the medulla∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙ ∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙ M. metarevoluta (Asahina) Elix & Hale 5. Medulla P -, lacking galbinic acid; moniliform cells absent in the medulla ∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙ ∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙ M. aurulenta (Tuck.) Elix & Hale 6. Upper surface distinctly rugose, often bursting open along the ridges of wrinkles; upper cortex fragile and easily flaking away, exposing medulla ∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙ ∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙ M. entotheiochroa (Hue) Elix & Hale 6. Upper surface smooth, cortex almost entire ∙∙∙∙∙∙∙∙∙∙∙∙ 7 7. Thallus rather tightly adnate; medulla P+ brick red, containing galbinic acid; moniliform cells present in the medulla∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙ M. galbina (Ach.) Elix & Hale 7. Thallus adnate; medulla P - or P+ yellow, lacking galbinic acid; moniliform cells absent in the medulla∙∙ ∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙ M. irrugans (Nyl.) Elix & Hale

Published as part of Moon, Kwang Hee, Ahn, Chorong & Kashiwadani, Hiroyuki, 2015, Revision of the lichen genus Myelochroa (Ascomycotina: Parmeliaceae) in Korea, pp. 23-32 in Journal of Species Research 4 (1) on pages 30-31, DOI: 10.12651/JSR.2015.4.1.023, http://zenodo.org/record/8120342