PLATE XVII. 



Fig. 10. Apex of bleached leaf of X. globosum showing serration. 

 X 11. W, clusters of tracheids; X, hairs from leaf. 



Fig. 11. Cross section of midrib of leaf of X. globosum. x 27. A, 

 photosynthetic tissue; B, water-storage cells; C, collenchyma of midrib; 



D, epidermis; X, xylem of vascular bundle; Y, phloem. 



FlG., 12. Cross section at the base of leaf of X. pennsylvanicum. x 17. 



E, vasular bundle; F, collenchyma; G, resin duct; H, photosynthetic cells; 

 /, water-storage cells; J, midrib of leaf. 



FlG. 13. Tracheids from leaf of X. globosum. x 193. 



FlG. 14. Stomata from leaf of X. globosum. X 193. K, epidermal 

 cells; L, photosynthetic cells; M, stoma. 



Fig. 15. Epidermis of midrib of leaf of -Y. pennsylvanicum. X 200. 

 N, epidermis. 



Fig." 16. Tangential section of epidermis from the bleached leaf of 

 A', globosum. X 200. O, stoma. 



Fig. 17. Tangential section of epidermis of the leaf of X. americanum. 

 X 193. Q, cells at base of hairs; R, stoma; S, epidermal cells. 



Fig. 18. Trichomes on leaf of X. americanum. x 193. T, cells at 

 base of hairs. 



Fig. 19. Tangential section from bleached leaf of X. pennsylvanicum. 

 X 200. U, stoma. 



FlG. 20. Tangential section from bleached leaf of X. americanum. 

 X 200. V, stoma. 



Fig. 21. Central vascular bundle from leaf of X. pennsylvanicum, 

 X 127. W, vessels; X, phloem. 



Fig. 22. Composite drawing of leaf of X. globosum. x 193. Y, 

 vessels; Z, border parenchyma; A, epidermal cells; B, cells at base of 

 hairs; C, stoma; D, basal cell of hair; E, linear hair; F, pointed hairs. 



