Fig. 253. Eupatorium perfoliatum.
—Portion of plant and flower (enlarged).
This image is from Eupatorium in Sayre's Manual of Organic Materia Medica and Pharmacognosy, 1917.
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.