776 BOTANY AND PHARMACOGNOSY. 



i8o. VIBURNUM PRUNIFOLIUM. (See No. 177.) 



181. XANTHOXYLUM. Dark brown; calcium oxalate in 

 monoclinic prisms 10 to 25 /x in diameter; starch grains nearly 

 spherical, 4 to 10 /x in diameter; oil-secretion cells colorless; cork 

 cells strongly lignified ; bast fibers few, thick-walled, slightly ligni- 

 fied, swelling perceptibly in chloral (Fig. 238). 



In Southern Prickly Ash (Fig. 233) occur groups of large, 

 more or less lignified sclerenchymatous cells, and the lignified 

 cork cells are more numerous. 



y Calcium Oxalate in Crystal Fibers. 



182. OUERCUS ALBA. Light brown (Figs. 135, 300); 

 bast fibers long, thick-walled, lignified ; crystal fibers containing 

 rosette aggregates or monoclinic prisms of calcium oxalate about 

 10 to 20 fi in diameter ; stone cells thick-walled, with numerous 

 lamellae and simple pores (Fig. 301, A) ; parenchyma with irregu- 

 lar yellowish-brown tannin masses. 



b. CALCIUM OXALATE WANTING. 



a Containing Pollen Grains. 



183. ARNICA FLORES. (See No. 81.) 



184. CROCUS. (See No. 85.) 



185. SANTONICA. Light brown (Fig. 240) ; pollen grains 

 nearly spherical, nearly smooth, 3-pored, 15 to 20 /* in diameter; 

 glandular hairs of two kinds, either with i or 2 short cells or with 

 2 to 3 pairs of cells. If a few c.c. of an alcoholic (95 per cent.) 

 extract be heated with a few drops of potassium hydrate solution, 

 a reddish color is produced. 



/? Pollen Grains Wanting. 

 I. Stone Cells Numerous. 



186. CUBEBA. Light brown (Fig. 250) ; stone cells single 

 or in isolated groups, nearly isodiametric, thick-walled, with nu- 

 merous simple pores, and colorless or light-yellow contents ; scler- 

 enchymatous fibers few, short, thick-walled, strongly lignified; 

 parenchymatous cells with reddish-brown tannin masses ; oil-secre- 



