IV. SOME INTER-RELATIONS OF PLANTS AND ANIMALS 75 V. PLANT STRUCTURES 98 VI. PLANTS AND MAN 135 VII. PAST AND PRESENT 155 VIII. SOME INTERESTING BRITISH PLANT GROUPS 180 INDEX 208 LIST OF ILLUSTRATIONS FRONTISPIECE.--Desert types: 1, _Rhipsalis pachyptera_. 2, _Haworthia Chalwinii_. 3, _Cereus celsianus_. 4, _Cereus nigricans_. 5, _Aloe Davyana_. 6, _Cotyledon undulata_. 7, _Haworthia tesselata_. 8, _Crassula columnaris_. 9, _Mammillaria plumosa_. 10, _M. obcordellum_. 11, _Mesembryanthemum Pearsoni_. 12, _M. Lesliei_. 2, 5, 6, 7, 8, 10, 11, 12, from South Africa. 1, 3, 4, 9, from Central and South America. FIG. PAGE 1. A Burrowing Lichen, _Verrucaria calciseda_ 17 2. The Glasswort, _Salicornia europæa_ 18 3. _Mesembryanthemum Bolusii_ and _M. Lesliei_ 21 4. Wild Carrot, _Daucus Carota_ (grown under great exposure) 37 5. Inrolled Leaf of Crowberry, _Empetrum nigrum_ 39 6. Succession of Vegetation in Lakes: _a_, Marsh Zone. _b_, Reed Zone. _c_, Zone of Floating Vegetation. _d_, Zone of Submerged Vegetation (diagrammatic) 43 7. Coral Root, _Dentaria bulbifera_ 54 8. Fruit of Giant Bell-flower, _Campanula latifolia_ 56 9. Fruit of _Geranium_ 58 10. Fruit of _Viola_ 59 11. Fruit of _Erodium_ 60 12. Diagram illustrating Fall of Seeds 64 13. Wing-seeds and Plume-seeds 68 14. Flower of _Erodium_ 85 15. Flower-head of _Astrantia_ 86 16. Dwarf Cornel, _Cornus suecica_ 88 17. Japanese Wineberry, _Rubus phœnicolasius_ 90 18. Flower and Fruit of Purple Toad-flax, _Linaria purpurea_ 93 19. Stem and Root Structure 112 20. _Genista sagittalis_ 118 21. Leaf-mosaic in _Azara microphylla_ 121 22. Leaf of _Weinmannia trichosperma_ 122 23. Leaf-development of Arrow-head, _Sagittaria sagittifolia_ 125 24. Fruit of _Coriaria japonica_ 128 25. Wild Cabbage, _Brassica oleracea_ 150 26. A Myxomycete, _Comatricha typhoides_ 158