CH. IV. 



MISCELLANEOUS. 



117 



of pot plants. In pots, from want of room, or from 

 want of w^ater, or from exposnre to frost, the roots on 

 the outsides of the balls of earth may die, while the 

 parts inside the balls of earth may survive. But trees 

 in good health and in good soils never lose a rootlet. 

 On the contrary, the rootlets continue to grow each 

 year for months after the stems have ceased to grow, 

 and after they have shed their leaves ; possibly through 

 the whole of a mild winter. In October, 1854, I 

 scraped some mud out of a pond, the water of which 

 was low ; I accidentally laid this mud in heaps on 

 some horse-chestnut roots, which had been bared of 

 earth by the tread of cattle. On the 26th of the fol- 

 lowing December I removed the heaps, and found them 

 full of new roots, which were aioparently in full shoot 

 then ; many had silver ends six or eight inches long. 

 This late growth of the root is, as I have said above, a 

 strong reason for summer and autumn transplanting, 

 where it can be done with a ball of earth, that is, with- 

 out exposing the roots to drought. 



We may convince oiu-selves by experiment that 

 the downward is after the upward growth of trees. If 

 notches are cut on the stem of a tree from the root to 

 the setting on of the first branches, the new growth 

 over the scars will be when the tree is ceasing to shoot. 

 The upper notches will heal first, in the form of a 

 horseshoe, with the heels downwards ; that is, the 

 growth will be on the upper part and the sides of the 

 notches, without any growth from the loAver parts of 



