458 SCIENTIFIC AND APPLIED PHARMACOGNOSY 



A 



FIG. 199. Cactus: A, transverse section of stem; E, papillose epidermis; Hy, 

 hypodermis; P, cortical parenchyma containing chloroplasts (Chi); Ca, 

 solitary crystals of calcium oxalate from 0.015 to 0.400 mm. in length; Mu, 

 mucilage cells. B, transverse section of the fibrovascular bundles: Bf, bast 

 fibers; M, broad medullary rays, the cells containing starch; L, leptone; 

 Cam, cambium layer; T, tracheae; W, wood fibers; P, starch-bearing paren- 

 chyma (<S), the grains from 0.003 to 0.010 mm. in diameter; Mu, mucilage 

 cell. C, longitudinal section of xylem portion of bundle: M, parenchyma- 

 tous cells containing starch (<S); Ts, trachea? with large simple pores; Tr, 

 reticulate tracheae ; W, wood fibers. D, solitary crystals of calcium oxalate. 

 Drawing by Haase. 



