454 



BOTANY AND PHARMACOGNOSY. 



A 



Fig. 196. Peruvian rhatany: A, transverse section showing cork (k), a group of 

 bast fibers (sk), parenchyma of cortex (p), one cell near the middle containing a mono- 

 clinic prism of calcium oxalate (o), medullary-ray cells of bark (m), cambium (c), tracheae 

 (t), wood fibers (sc), wood parenchyma (hp), medullary-ray cells (m); B, bast fiber; C, 

 wood fiber with neighboring parenchyma cells which are somewhat elongated and have 

 somewhat thickened, porous walls; D, trachea. — After Meyer, 



