PLATE XLIII. 



Lesquerella spathulata. 



Fig. 37. Cutinized epidermis of stem, cross section: S, outer tangential 

 wall; T, inner tangential wall, x 650. 



Fig. 38a. Cutinized epidermis of stem, longitudinal section: S, outer 

 tangential wall; T, inner tangential wall, x 650. 



Fig. 386. Cork cells as seen in cross section, x 650. 



Fig. 39. Stone cells found in the borke, cross section, x 650. 



Fig. 40. Collenchyma cells, cross section. X 650. 



Fig. 41. Collenchyma cells, longitudinal section, x 650. 



Fig. 42. Stone cells found in sclerenchyma tissue, cross section, x 650. 



Fig. 43. Stone cells found in sclerenchyma tissue, longitudinal section. 

 X 650. 



Fig. 44. Bast fibers, longitudinal section, x 650. 



Fig. 45. Bast fibers, cross section, x 650. 



Fig. 46. Small portion of xylem, cross section: A, wood fibers; B, wood 

 parenchyma cells; C, tracheal elements. 



Fig. 47, Wood fiber, longitudinal section, x 650. 



Fig. 48. Tracheal elements found in the stem at the nodes as seen in 

 longitudinal section: A, scalariform type of tracheids; B, 

 spiral type of tracheids. x 650. 



Fig. 49. Tracheal elements found in the internodes of the stem, as seen 

 in longitudinal section: A, spiral tracheal tubes found among 

 the wood fibers; B, spiral tracheal tubes found among the 

 wood parenchyma cells; C, scalariform tracheal tubes, x 650. 



Fig. 50. Diagrammatic drawing of the cross section of the stem: A, 

 borke; B, collenchyma; C, sclerenchyma; D, phloem; E, 

 xylem; 1, tracheal tissues; 2, wood fibers; 3, xylem pa- 

 renchyma; F, medullary ray; a, leaf trace. X 87^- 



