92. Plants which have no peculiar spot for their growth: others that grow upon trees, and will not grow in the ground. Nine varieties of them: cadytas, polypodion, phaulias, hippophæston 433 93. Three varieties of mistletoe. The nature of mistletoe and similar plants 434 94. The method of making birdlime 435 95. Historical facts connected with the mistletoe 435 BOOK XVII. THE NATURAL HISTORY OF THE CULTIVATED TREES. 1. Trees which have been sold at enormous prices 438 2. The influence of weather upon trees: what is the proper situation for the vine 441 3. What soils are to be considered the best 446 4. The eight kinds of earth boasted of by the Gauls and Greeks 452 5. The employment of ashes 455 6. Manure 456 7. Crops which tend to improve the land: crops which exhaust it 459 8. The proper mode of using manure _ib._ 9. The modes in which trees bear 460 10. Plants which are propagated by seed _ib._ 11. Trees which never degenerate 461 12. Propagation by suckers 463 13. Propagation by slips and cuttings 464 14. Seed-plots _ib._ 15. The mode of propagating the elm 467 16. The holes for transplanting 468 17. The intervals to be left between trees 472 18. The nature of the shadow thrown by trees 473 19. The droppings of water from the leaves 474 20. Trees which grow but slowly: those which grow with rapidity 475 21. Trees propagated from layers _ib._ 22. Grafting: the first discovery of it 477 23. Inoculation or budding _ib._ 24. The various kinds of grafting _ib._ 25. Grafting the vine 482 26. Grafting by scutcheons 483 27. Plants which grow from a branch 485 28. Trees which grow from cuttings: the mode of planting them 486 29. The cultivation of the olive _ib._