752 



BOTANY AND PHARMACOGNOSY. 



crystals. /. nigra has also in the medullary rays rosette aggre- 

 gates of calcium oxalate. /. regia appears more nearly to resem- 

 ble /. cinerea. 



107. ARALIA NUDICAUUS (American Sarsaparilla).— 

 Light brown; rosette aggregates of calcium oxalate varying 

 from 35 to 70 /x; spherical starch grains, from 10 to 15 /x; 

 tracheae with scalariform and reticulate thickenings, also sitpple 

 and bordered pores; wood fibers long, with slightly thickened 

 walls and simple pores; large oil glands, and brown cork cells. 



Fig. 299. Several forms of sclerenchymatic fibers: A, intermediate fibers from wood 

 of ipecac showing lignified walls with oblique simple pores and one cell containing starch; 

 B, t)ast fibers from cinchona showing in transverse section a stratification of the wall, 

 and in longitudinal section a striation of the walls; C, longitudinal section of quassia showing 

 tracheids with bordered pores and medullary-ray cells. 



108. STILLINGIA. — Light brown; sclerenchymatous fibers 

 very long, thick-walled and swelling perceptibly in potassium 

 hydrate solution; starch grains spherical or ellipsoidal, 15 to 30 /*, 

 in diameter ; secretion cells containing oil, resin and a brown pig- 

 ment; calcium oxalate crystals rosette-shaped, 35 f/. in diameter. 



109. EUONYMUS.— Light brown (Fig. 300, E) ; bast fibers 

 long, thin-walled, non-lignified, the walls frequently modified to 

 mucilage and possessing numerous small, more or less oblique 

 pores, and irregular ends ; starch grains spherical, 4 to 10 /* in 



