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. 

 Cork cells as seen in cross section, x 650. 

 Stone cells found in the boi'ke, cross section. X 650. 

 Collenchyma cells, cross section, x 650. 

 Collenchyma cells, longitudinal section. X 650. 

 Stone cells found in sclerenchyma tissue, cross section. X 650. 

 Stone cells found in sclerenchyma tissue, longitudinal section. 

 X 650. 



Bast fibers, longitudinal section, x 650. 

 Bast fibers, cross section. X 650. 



Small portion of xylem, cro.ss section: A, wood fibers; B, wood 

 parenchyma cells; C, tracheal elements. 



Wood fiber, longitudinal section, x 650. 



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. Trachea] 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%, 



