THE AUSTRALIAN GREY MANGROVE. 281 



overcame this defect by placing keys between them, and 

 thus preventing a shearing upon each other when subjected 

 to a great weight. 



Explanation of Plates XXVII - XLVI. 



Fig. 1. Transverse section of a portion of leaf showing central 

 bundle, and neighbouring tissue. x 150. 



„ 2. Transverse section of a portion of a leaf showing a depres- 

 sion on the upper surface. x 50. 



,, 3. Higher magnification of Fig. 2, showing structure of 

 depression and surrounding tissue. x 150. 



„ 4. Transverse section of breathing root below mud surface. 

 x 30. 



„ 5. Longitudinal section of breathing root below mud sur- 

 face, x 15. 



„ 6. Transverse section near the tip of air and tide exposed por- 

 tion of a pneumatophore, but cutting central root, x 30. 



.,, *7. Transverse section near the tip of air and tide exposed 

 portion of a pneumatophore, but cutting central root 

 lower down than Fig. 6. x 30. f 



„ *8. Longitudinal section through tip of a pneumatophore. 

 x 30. 



„ 9. Series showing germination of seed (natural size). 



„ 10. Transverse section of a trunk of a tree (reduced.) 



,, 11. Transverse section of trunk of tree (enlarged from 10). 



„ 12. Tangential view of split wood showing disposition of fibres. 



,,*13. Transverse section of primary growth. x 30. 



„ 14. Transverse section of later growth. x 100. 



,,*15. Transverse section of G years old wood. x 15. 



,, 16. Transverse section of secondary wood, x 35. 



„ 17. Tangential section of secondary wood, x 35. 



,, 18. Radial section of secondary wood. x 35. 



,, 19. Seven years' old " Grey Mangrove" trees, 5 feet high. 



,, 20. "Grey Mangrove" out-spreading over air and tide exposed 

 portion of breathing roots. 



* Coloured Plates. 



t Plate XXXIII read Fig. 6 instead of Pig. 4. 



