458 



EDWARD C. JEFFREY ON 



Dr. D. H. Scott, Prof. D. P. Penhallow, Prof. C. V. Piper, Professors Farlow, Goodale, 

 Robinson, and Thaxter, and last but not least, to Mr. George S. Shaw, chairman of the 

 visiting committee on botany. 



Botanical Museum of Harvard University, 

 Cambridge, Mass. 



Explanation of Plates. 



All the figures are from photomicrographs. 

 PLATE 68. 



Fig. 1. Transverse section of the wood of Sequoia gigantea. X 50. 



Fig. 2. Transverse section of a branch of a young tree of S. gigantea. x 60. 



Fig. 3. Transverse section of a vigorous branch of an adult tree of S. gigantea. X 40. 



Fig. 4. Transverse section of the medullary region of a similar branch, x 100. 



Fig. 5. Medullary region of a similar branch from another adult tree of S. gigantea. X 50. 



Fig. 6. Transverse section of the woody portion of the peduncle of an old cone of S. gigantea. X 30. 



Fig. 7. Transverse section of the central portion of the same, x 50. 



Fig. 8. Higher region of the peduncle of the same cone. X 30. 



PLATE 69. 



Fig. 9. Transverse section of the medullary region between those shown in figures 6 and 8. x 50. 



Fig. 10. Transverse section through the axis of the cone of 8. gigantea. X 40. 



Fig. 11. Transverse section of the woody axis of the base of a cone scale in S. gigantea. X 50. 



Fig. 12. Transverse section of the woody axis of another cone scale of S. gigantea. X 50. 



Fig. 13. Transverse section through the upper portion of a cone scale of S. gigantea. X 3. 



Fig. 14. Transverse section of part of the same. X 50. 



Fig. 15. Transverse section of another part of the same. X 50. 



Fig. 16. Transverse section through an abnormal bundle of the cone scale of 6'. gigantea. X 60. 



PLATE 70. 



Fig. 17. Transverse section of the woody part of the axis in a five year old seedling of S. gigantea. X 40. 



Fig. 18. Transverse section through part of an injured root of S. gigantea, showing the formation of traumatic resin 

 ducts in a tangential row. X 40. 



Fig. 19. Transverse section through part of the peduncle of a wounded cone of S. gigantea. X 50. 



Fig. 20. Transverse section of the upper portion of the woody axis of a female cone of Abies grandis, showing the 

 presence of resin canals. X 40. 



Fig. 21. Transverse section through the woody axis of the cone of Abies balsatnea, showing the absence of resin ducts. 

 X 35. 



