Parmotrema conferendum Hale, 1977
Parmotrema conferendum is distinguished by the usually capitate, marginal to submarginal soralia, and medulla with norlobaridone and loxodin (K–, KC+ reddish). The morphologically similar species differ mostly in chemical constituents: P. subsumptum has salazinic and consalazinic acids, reacting K+ yellow → blood red, and P. reitzii Hale produces salazinic acid and norlobaridone (Hale 1977), the medulla being K+ yellow → blood red and KC+ reddish.
Parmotrema reitzii was placed as synonym of Rimeliella conferenda by Kurokawa (1991), and as synonym of Rimeliella subsumpta by Fleig (1997). However, Elix (1997) accepted P. reitzii as distinct, an opinion kept here.
Parmotrema larense López-Figueiras has, in addition to norlobaridone, lichexanthone in the medulla (Mata García 1994), being UV+ yellow-orange.
[Spielmann & Marcelli 2009]