POWDERED DRUGS AND FOODS. 



753 



diameter; cork, thin-walled, white; secretion cells with yellowish 

 or brownish masses; rosette aggregates of calcium oxalate, 15 to 

 20 IX in diameter. The stem-bark as well as the whole twigs of 

 E. atropurpureus are frequently admixed with or substituted for 

 Euonymus. 



Fig. 300. Various forms of sclerenchymatic fibers: A, intermediate fiber of gentian 

 the walls consisting of cellulose and having simple oblique pores; B, transverse section of 

 a group of bast fibers in white oak bark, and a few crystal fibers; C, portions of two bast 

 fibers from krameria; D, sclerenchymatous fiber from leaf of uva ursi; E, portion of modi- 

 fied bast fiber of euonymus; F, portions of bast fibers and a crystal fiber of white oak bark 

 ■ G, portions of sclerenchymatous fibers of quillaja showing unequal thickening; H, portion 

 of bast fiber of cotton root bark; I, isolated sclerenchymatous fiber of ginger. 



1 10. RUMEX. — Dark brown; calcium oxalate in rosette 

 aggregates from 20 to 35 /x in diameter ; starch grains numerous, 

 ellipsoidal or narrowly elongated, from 10 to 18 /x in length ; stone 



48 



