433 



FIG. 189. Transverse section of cottom root bark showing the characteristic 

 cone-shaped strands of leptome: C, layers of cork; Cr, rosette aggregates of 

 calcium oxalate from 0.010 tc 0.025 mm. in diameter; B, bast; N, medullary 

 rays; T, cells containing tannin; S, leptome. After Morgan. 



