364 SCIENTIFIC AND APPLIED PHARMACOGNOSY 



secretory cavities having light yellow oily globules; medullary 

 rays mostly one cell in width; the parenchyma cells as well as the 

 oil secretion cavities contain numerous colorless oily globules. Scrap- 

 ings from the inner surface show numerous rod-shaped crystals and 

 flat prisms from 0.015 to 0.250 mm. in length, which polarize light 

 with a display of bright colors. 



Southern Prickly Ash. Transversely curved or irregularly oblong 

 flattened pieces, occasionally in single quills 5 to 30 cm. in length, 

 1 to 7 cm. in diameter, 1 to 4 mm. in thickness; outer surface with 

 numerous conical cork-wings or their scars; inner surface free from 

 crystals. 



Inner Structure. (Fig. 159.) Periderm of strongly lignified cork 

 in the form of rings, the successive layers being separated by 

 several rows of narrow tabular cells, strongly thickened on the tan- 

 gential walls; a thin layer of collenchyma; tissues of the primary 

 cortex contain small groups of rather large stone cells and occa- 

 sional scattered groups of bast fibers and parenchyma; the inner 

 bark consists of parenchyma, a more or less indistinct leptome or 

 sieve tissue and among which are numerous large, light-yellowish 

 oil-secretion cavities, and occasional groups of stone cells and bast 

 fibers; medullary rays from 1 to 2 cells in width; starch grains 

 numerous, nearly spheroidal, from 0.002 to 0.010 mm. in diameter, 

 and occurring in the parenchyma cells and medullary rays; calcium 

 oxalate chiefly in monoclinic prisms from 0.010 to 0.025 mm. in 

 diameter, occurring in crystal fibers and in parenchyma cells of 

 the primary cortex. 



Powder. Light grayish-brown or dark brown; calcium oxalate in 

 monoclinic prisms, frequently in crystal fibers; starch grains small 

 and nearly spheroidal ; oil secretion cavities having a nearly colorless 

 or light yellowish oil; cork cells strongly thickened and lignified; 

 bast fibers, thick walled, slightly lignified, swelling perceptibly in 

 hydrated chloral. 



In Southern Prickly Ash occur groups of large, more or less lig- 

 nified sclerenchymatous cells, and the lignified cork cells are more 

 numerous. 



Constituents. Two resins, one acrid, the other crystalline and 

 bitter; an acrid volatile oil; a bitter, alkaloidal principle, somewhat 

 resembling berberine; a crystalline phenol compound zanthoxylin; 

 ash about 12 per cent. 



Allied Plants. The fruits both of Zanthoxylum americanum and 

 Z. Clava-Herculis are found in commerce and known as Prickly Ash 

 berries. They consist of 2 to 3 follicles, each of which is 5 to 6 mm. 



