Iris. Fig. 3.—Crystals of calcium oxalate from rhizome
Fig. 3.—Crystals of calcium oxalate from rhizome. Magnification, 150 diameters.
This image is from Structure of Iris. in the American Journal of Pharmacy, 1895.
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.