PLATE VIII. 



Fig. 15. — Transverse section of a vascular cylinder with its more external 

 cortical layer and the bases of three rootlets. Medullary cavity, a. Wedges of 

 the vascular cylinder, b. Outermost cortical parenchyma, d. Meristem zone of 

 bark, d' . Cortical prosenchyma, e. Rootlet bundle, /. Rootlet bundle cylinder, 

 /". Cortical zone of rootlet, g. Rootlet cushion, h. X 6^-. Cabinet, No. 759. 

 (Pages 14, 18, 26.) 



Fig. 22. — Outer cortex of a transverse section from the same specimen as 

 Fig. 15. Outermost parenchyma, d. Meristem or bark cambium zone, d'. Pro- 

 senchymatous zone, e. X 18. Cabinet, No. 757. (Pages 19, 20, 21, 43.) 



Fig. 23. — Transverse sections of the cortex of a much older Stigmarian root 

 than Fig. 22. Outermost cortical parenchyma, d. Meristem zone, d'. Cell walls 

 of mother cells ? d" . Prosenchymatous zone, e. X 18. (Pages 19, 20, 21, 43.) 



Fig. 24. — Tangential section through the meristem tissue, d', of Fig. 23. 

 Boundaries of mother-cells, identical with those of d" of Fig. 23. X 9. 

 (Page 20.) 



Fig. 24a. — Tangential section of the tissue, e, of Fig. 23. x 9. (Pages 

 20, 21.) 



