Fig. 169. Rhamnus frangula - Cross-section of bark.

Fig. 169. Rhamnus frangula - Cross-section of bark...

(37 diam.) A, Cork. B, Group of bast fibers. C, Medullary ray. (Photomicrograph).

This image is from Frangula in Sayre's Manual of Organic Materia Medica and Pharmacognosy, 1917.