Parmotrema recipiendum (Nyl.) Hale, 1974
Parmotrema recipiendum is distinguished by the lack of vegetative propagules and the presence of norlobaridone and loxodin (medulla K–, KC+ reddish). Parmotrema subcaperatum (Kremp.) Hale is very similar morphologically, so much that the two species were already synonymous (Hale 1965). The last one, however, has salazinic and consalazinic acids (medulla K+ yellow → blood red). On the other hand, Parmotrema cristobaliae (Ferraro & Elix) Blanco, Crespo, Divakar, Elix & Lumbsch and P. erubescens (Stirton) Krog & Swinscow have in medulla both norlobaridone and loxodin as well as salazinic acid (Krog & Swinscow 1981, Ferraro & Elix 1993). Finally, Parmotrema conferendum has the same chemical pattern of P. recipiendum, but is a sorediate species.
[Spielmann & Marcelli 2009]