PLATE XXXIX. 



Fig. 15. Wood fibers. X 230. 



Fig. 16. Cross section in stem, x 390. a, phloem; h, parenchyma of 

 pericycle; c, starch sheath; d, starch; ■^, center. 

 Fig. 17. Compound grains of starch, x 995. 

 Fig. 18. Xylem parenchyma, x 255. 



Fig. 19. Longitudinal section of secondary phloem x 255. a, calcium 

 oxalate crystals. 



Fig. 20. Longitudinal section of stem; primary bundles. x 390. 

 a, xylem parenchyma; 6, pith. 



Fig. 21. Tracheids and trachea; mascerated sections, x 390. 



