iio3 
Relationships of the Gnetales. 
gamic Laboratories of Harvard University, as an 1851 Exhibition Science 
Research Scholar of the University of Toronto. He is indebted to Professor 
E. C. Jeffrey for material and advice. 
EXPLANATION OF PLATES XCIV-XCVII. 
Illustrating Mr. Thompson’s paper on the Gnetales. 
PLATE XCIV. 
Fig. 1. E. monostachya : transverse section of entire young branch, x 60. 
Fig. 2. E. trifurca : transverse section, showing group of pith cells simulating centripetal 
wood, x 125. 
Fig. 3. E. altissima : radial section through region of node, showing peridermal diaphragm, 
x 30. 
Fig. 4. E. altissima : transverse section through lower part of node, showing girdle of primary 
tracheides. x 125. 
Fig. 5. The same : section through node at exit of trace, showing the double character and 
separation of strands by a block of wood, x 125. 
Fig. 6. E. trifurca : nodal section, showing double trace whose strands are not separated by 
wood, x 100. * 
Fig. 7. E. altissima : Tangential section through node, showing two strands of leaf-trace 
separated by wood, x 125. 
Fig. 8. E. vulgaris : centripetal transfusion tracheide at node, x 667. 
Fig. 9. E. monostachya : transfusion tracheides in internode, x 667. 
Fig. 10. E. monostachya : transverse section of secondary wood, x 500. 
Fig. 11. E. trifurca , root : radial section, showing Abietinean pitting and bars of Sanio. x 667. 
Fig. 12. E. distachya : compressed Araucarian pitting and normal vessel, x 500. 
PLATE XCV. 
Fig. 13. E. trifurca, root : tangential pits, bars of Sanio, and broad ray. x 500. 
Fig. 14. E. californica\ tertiary spirals, x 667. 
Fig. 15. E. Gerardiana : thickenings around pits, x 500. 
Fig. 16. E. trifurca'. showing trabeculae, x 500. 
Fig. 17. E. altissima : tangential section, showing perforations in end wall of vessel, x 500. 
Fig. 18. E. Gerardiana : tangential section near pith, showing perforations in association with 
bordered pits, x 500. 
Fig. 19. E. gerardiana'. tracheide showing first stage in transition to a vessel, x 667. 
Fig. 20. E. monostachya : vessel showing gradual loss of torus and border, x 500. 
Fig. 21. E. distachya : vessel showing fusion of perforations, x 667. 
Fig. 22. E . calif ornica : parenchyma cell whose pits are slightly bordered, x 667. 
Fig. 23. E. distachya : wood -parenchyma cell with two nuclei, x 500. 
Fig. 24. E. trifurca : wood-parenchyma cell, showing nucleus dividing, x 500. 
PLATE XCVI. 
Fig. 25. E. monostachya : septated wood-parenchyma cell and normal vessel, x 500. 
Fig. 26. E. distachya : radial section of medullary ray. x 500. 
Fig. 27. E . altissima, seedling: transverse section, x 60. 
Fig. 28. E. altissima , seedling: tangential section near pith, showing formation and enlarge- 
ment of medullary rays by transformation of tracheides. x 125. 
Fig. 29. E. monostachya : transverse section, showing compounding of rays and dip in annual 
rings, x 30. 
Fig. 30. Transverse section of wood of E. calif ornica, x 10. 
