Parmelia sulc2837l.jpg

Parmelia sulcata, showing the spot test reactions with K, the upper arrow indicating the K+ yellow of the upper cortex and the lower arrow indicating the K+ yellow turning deep red of the medulla. TLGB&I (2009) gives the following reactions for P. sulcata: Cortex K+ yellow to red; medulla K+ orange. The erroneous reactions given by TLGB&I may have resulted from observations of over-generous application of reagent resulting in the medullary reaction seeping up into the upper cortex.