Fig. 297. Powdered Rhubarb.

(x 183.)
A, Fragments of reticulate water tubes.
B, Spiral water tube.
C, Aggregate crystals of calcium oxalate.
D, Starch.
E, Parenchyma.
F, Phloëm.
This image is from Rheum in Sayre's Manual of Organic Materia Medica and Pharmacognosy, 1917.

Fig. 297. Powdered Rhubarb.