Fig. 338, 339, 340. Microscopic structure of Calisaya bark.

Fig. 338. Transverse section of the entire thickness of a piece of bark with a poriton of the periderm attached.
Fig. 339. Transverse section of a portion of the liber (much more highly magnified than in Fig. 338).
Fig. 340. Longitudinal section of a portion of the liber made parallel to the medullary rays.
pd, Portion of periderm. l, Liber. cc, Cellular tissue of the liber. fl, Ligneous fibres of the liber (cortical fibres). rm, Medullary rays.

This image is from _ in Pereira's Elements of Materia Medica and Therapeutics, 1854.