viii MANUAL OF BOTANY 



BOOK IV. 



PHYSIOLOGY OF PLANTS. 



CHAPTEK I. 



PAdE 



The Eelation of Wateb to the Pkotoplasm of the Cell 409 



Arrangement of the protoplasm 410 



Absorption of water . . 411 



Osmosis ........... 411 



Influence of the protoplasm on osmosis . . . . 412 



CHAPTER II. 



The Transpokt of the Water in the Plant . 416 



Absorption of water from the soil 416 



Transport of water through the plant 418 



Evaporation of water, or transpiration 419 



CHAPTER III. 



The Skeleton of the Plant . . . 423 



Arrangements to secure rigidity 420 



Character of the cell-walls . . . . . . . 421 



Supporting tissues 423 



CHAPTER IV. 



The Tbanspikation Current — Root-pressure — Transpiration 424 



Path of the current 425 



Root-pressure 425 



Transpiration 427 



CHAPTER V. 



The Food of Plants. Introductory . . . 431 



True nature of plant food 431 



The materials from which it is constructed 432 



