PLATE VII. 



Fig. 10. — A radial section through the outermost vessels, b, of the vascular 

 cylinder. Cambiform zone, c. Cells belonging to a more external cortical 

 parenchyma, d, d. X 90. Cabinet, No. 779 (Pages 13, 17, 18.) 



Fig. 11. — A tangential section through a portion of a vascular cylinder. Xylem 

 laminas, b. Secondary medullary rays, b'. Rootlet bundles, f. X 5. Cabinet, 

 No. 771. (Pages 11, 13, 15.) 



Fig. 14. — Transverse section of a medium-sized vascular cylinder. Medullary 

 cavity, a, containing an intruded Stigmarian rootlet, g. Vascular wedges, b. 

 Primary medullary rays, b'. Obliquely longitudinal sections of rootlet bundles, 

 normally co-extensive with the entire thickness of the cylinder, /. Section of a root- 

 let bundle escaping from the cylinder, /'. X 5. (Pages 13, 14, 17, 23, 25, 33, 35.) 



Fig. 26. — A portion of Fig. 25, further enlarged. External pressure has 

 disturbed the transversely intersected prosenchymatous cells along the lines, e, e. 

 X 18. (Page 20.) 



