ZANTHOXYLUM 



363 



rod-shaped crystals, phelloderm layer dark green, inner bark with 

 groups of converging medullary rays; odor slight; taste bitter, 

 acrid and pungent. 



Inner Structure. (Compose with Fig. 159.) Periderm of 

 strongly thickened and lignified cork cells; collenchyma of several 



FIG. 159. Southern prickly ash, Zanthoxylum (Fagara) Clava-Herculis : A, 

 transverse section showing cork (k), stone cells (si), groups of primary bast 

 fibers (6), calcium oxalate (ca), medullary rays (ra), parenchyma (p) contain- 

 ing starch, oil-secretion cavities (o), sieve (s), cambium (c). B, isolated stone 

 cells showing pores and lamella;. C, group of bast fibers found in young, 

 thin bark and surrounded by parenchyma (p). D, longitudinal section near 

 a group of bast fibers showing non-lignified bast fibers (6), calcium oxalate 

 (ca) in crystal fibers, medullary rays (m), parenchyma (p) containing starch. 



rows of thick-walled, tangentially elongated cells; a more or less 

 indistinct row of endodermal cells beneath which is an interrupted 

 circle of small groups of primary bast fibers; inner bark of numer- 

 ous starch-bearing parenchyma cells among which are included the 



