Fig. 166. Cetraria islandica.
a. The apothecia on the larger lobes of the thallus.
This image is from Iceland Moss in Pereira's Elements of Materia Medica and Therapeutics, 1854.
A herbal distance course
Henriette's herbal is one of the oldest and largest herbal medicine sites on the net. It's been online since 1995, and is run by Henriette Kress, a herbalist in Helsinki, Finland.