APPENDAGES OF THE AXOPHYTE. , 33 



older mass of cells, pushed forward by the growth of the cells 

 at b, immediately behind them. The cells of the point consist 

 of older, denser tissues, as inspection plainly shows; and as 

 these decay and fall away, they are replaced by the layer 

 beneath. The point of all root fibres is capped in this way. 



Fig. 8. 



It would appear from this that absorption does not take place 

 to any considerable extent at the apex of the root, but princi- 

 pally through the more recently formed tissues behind it, and 

 especially by those capillary cells or root hairs with which the 

 surface of all young and growing roots is usually covered. 

 These root hairs are in general more abundant and more 

 developed on plants growing in loose, dry sand. Such plants, 

 in order to obtain as much moisture as possible from the unfa- 

 vorable element in which they are placed, shoot forth from 

 every fibre an incalculable number of them. 



Roots produce radicle fibres and root-hairs instead of leaves, 

 and these organs like leaves are deciduous towards autumn, 

 being annually renewed every spring. Hence the best time 

 for transplanting is in winter, when the fibres are dead or 

 torpid, or in early spring before they are renewed. Trans- 

 planting after the season of growth has fully commenced is 

 always attended with more or less injury to the plant. 



4 



