194 SCIENTIFIC AND APPLIED PHARMACOGNOSY 



of 15 cm., occasionally entire, attaining a length of 3 dm. ; externally 

 reddish- to grayish-brown, upper or rhizome portions distinctly 

 annulate, showing stem scars or stem bases and numerous small 

 circular root scars; lower or root portion longitudinally wrinkled; 

 fracture either short and mealy, or tough and fibrous; cortex narrow, 

 reddish-brown, wood portion yellowish-brown to reddish-brown, 

 somewhat radiate, pith usually depressed; odor slight; taste 

 astringent, somewhat bitter and nauseous. 



Inner Structure. Outer layer of a single row of dark-brown 

 cells; a stratum of collenchyma of several rows of very narrow tan- 

 gentially elongated cells; parenchyma of cortex of thin-walled cells 

 and containing either starch or rosette aggregates of calcium oxalate 

 and distributed among which occur occasioned vascular bundles; 

 the stele is composed of numerous small vascular bundles with a 

 small number of tracheae separated by a cambium from the leptome 

 which is distinct and composed of rather thick-walled more or less 

 collapsed cells; pith composed of starch-bearing parenchyma and 

 calcium oxalate. Sections mounted in solutions of ferric salts are 

 colored bluish-green. The tannin cells may be determined by placing 

 the fresh drug in solutions containing about 7 per cent of copper 

 acetate. If sections are mounted in solutions of the alkalies they 

 are colored deep red, due to the presence of chyrsophanic acid. 



Powder. Dark brown; calcium oxalate in rosette aggregates 

 from 0.020 to 0.080 mm. in diameter; starch grains numerous, ellip- 

 soidal or narrowly elongated, from 0.003 to 0.025 mm. in length; stone 

 cells occurring beneath the cork cells, 0.040 to 0.125 mm. in diameter, 

 with walls that are somewhat lamellated, 0.015 to 0.020 mm. in 

 thickness and with few simple pores; cork cells light brown; scleren- 

 chymatous fibers wanting; tracheae about 0.100 mm. in width with 

 scalariform and reticulate thickenings of the wall. On mixing the 

 powder with water and adding a solution of one of the alkalies a 

 red color is produced. In Rumex hymenosepalus the parenchyma 

 cells are about 0.200 mm. in diameter, with reddish colored walls and 

 contain numerous spheroidal or ellipsoidal starch grains from 0.008 to 

 0.015 mm. in diameter; calcium oxalate crystals are few or wanting. 



Constituents. Several crystalline principles, viz. : Rumicin, a 

 principle isometric with chrysophanic; nepodin, which occurs in 

 in greenish prisms; and lapodin, which forms small needle-shaped 

 crystals. The drug also contains a small amount of tannin, which 

 is colored green with ferric salts. 



RADIX LAPATHI. Bitter Dock Root. The rhizome and roots 

 of Rumex obtusifolius (Fam. Polygonaceae), a perennial herb which is 



