PLATE XIX. 



Fig. 28. Large vascular bundle at angle of stem of X. globosum. X 193. 

 /, tracheal tube ; J, parenchyma ; K, bast ; L, phloem ; M, wood parenchyma. 



Fig. 29. Cross section of pith of stem of X. pennsylvanicum. X 133. 



Fig. 30. Cross section of pith of stem of X. americanum. x 133. 



Fig. 31. Cross section of pith of stem of X. globosum. X 133. 



Fig. 32. Cross section of pith of X. pennsylvanicum, showing calcium 

 oxalate crystals. X 193. N, calcium oxalate crystals. 



Fig. 33. Longitudinal section of pith of X. globosum. X 193. O, cal- 

 cium oxalate crystals. 



Fig. 34. Cross section of phloem from the stem of X. pennsylvanicum. 

 X 133. 



Fig. 35. Cross section of starch sheath from stem of X. globosum. 

 X 193. P, calcium oxalate crystals; Q, starch grains; R, starch sheath. 



Fig. 36. Cross section of starch sheath from the stem of .Y. ameri- 

 canum. x 193. S, starch sheath; T, starch grains; U, calcium oxalate 

 crystals. 



Fig. 37. Cross section of the starch sheath from the stem of X. globo- 

 sum. x 193. V, starch sheath; W, starch grains; X, calcium oxalate 

 crystals. 



