Fig. 208. Apocynum cannabinum.
—Cross-section. (28 diam.) A, Cork. B, Parenchyma of cortex. C, Medullary ray. D, Water tube. (Photomicrograph.)
This image is from Apocynum 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.