POWDERED DRUGS AND FOODS. 



741 



^2. AURANTII DULCIS CORTEX. Light brown; cal- 

 cium oxalate in monoclinic prisms 20 to 30 /x in diameter ; walls of 

 parenchymatous cells about 4 /x thick. 



y In Raphides. 



73. SCILLA. Light yellow ; calcium oxalate mostly in raph- 

 ides from 0.1 to I mm. in length; few tracheae and fragments of 

 epidermis (Fig. 281, B). 



Fig. 293. Ground flaxseed: p, epidermis; c, epidermal cells with broken cutinized 

 layer; E, parenchyma cells beneath the epidermis; f, short sclerenchymatic fibers; qu, 

 colorless cells beneath the sclerenchymatic fibers; g, pigment cells with thick porous walls 

 and yellowish-brown contents; C, cells of cotyledons containing aleurone grains. After 

 Moeller. 



b. CALCIUM OXALATE CRYSTALS WANTING. 



a Sclercnchymatous Cells or Fibers Present. 



I. Dark Pigment Cells Wanting. 



74. SINAPIS ALBA. Light yellow (Figs. 294; 302, E, F) ; 

 fragments of seed-coat with mucilaginous epidermal cells ; a sub- 

 epidermal collenchymatous layer of i or 2 rows of cells ; a layer 

 of radially elongated palisade or stone cells (forming the so- 

 called " beaker cells "), the walls of the lower part being slightly 

 thickened and polygonal in surface view ; two or more inner 

 layers of thin-walled colorless cells ; a single layer of cells con- 

 taining aleurone grains and fixed oil, and some obliterated cells, 



