PLATE VII. 



Fig. 26. Base of vascular bundle, x 500. v, Wood fibers; w, tracheal 

 tubes; x, lignified pith cells; y, xylem parenchyma. 



Fig. 27. Medullary ray. X 500. z, Xylem; a, pith; b, medullary ray 

 cells; c, cells resembling - wood fibers. 



Fig. 28. Cross section of portion of cortex from young stem, x 500. 

 d, Cuticle; e, epidermis; f, collenchyma. 



Fig. 29. Tracheal vessels, x 500. g, Pitted vessel; /?, vessel with 

 spiral thickenings. 



Fig. 30. Cross section of phloem. X 500. 



Fig. 31. Cross section of bast, x 500. 



Fig. 32. Longitudinal section of wood fibers. X 500. 



Fig. 33. Longitudinal section of wood parenchyma, x 500. 



Fig. 34. Cross section of portion of cortex of old stem. X 500. i, Epi- 

 dermis; j, collenchyma. 



Fig. 35. Diagram of flower scale, x 120. k, Water-storage tissue; /, 

 vein; m, photosynthetic tissue. 



Fig. 36. Cross section of tissue separating two bast groups, x 580. 

 ft, Collenchyma; o, bast; p, starch sheath, showing portion not lignified; 

 q, thin-walled cells separating bast groups. 



Fig. 37. Longitudinal section through cortex, x 300. r, Epidermis; 

 t, collenchyma; s, starch sheath. 



