You could be right, mallyh:
Orcein, also archil, orchil, lacmus, litmus, Citrus Red 2, and C.I. Natural Red 28, are names for dyes extracted from several species of lichen, also called orchella weeds, found in various parts of the world. The manufacture was described by Cocq in 1812 and in the UK in 1874 . ...
http://en.wikipedia.org/wiki/Archil