PLANTING 53 



sand, so that the abundant roots fonred might, when they 

 reached the surrounding soil, find such substances as they 

 required to continue their growth. But the results proved 

 otherwise ; experiments with 36 different kinds of trees showed 

 little or no advantage as regards those planted 'in the sand pits 

 (IX, 33). Still more unsatisfactory results were obtained when 

 cuttings of various sorts were put into holes dibbed in the 

 ground and filled with sand, the number which struck being 

 less than half of those which struck when imbedded in earth. 



These results led to an investigation as to what happens 

 as regards the water present when masses of sand and soil are 

 in contact with each other, and it was found that under such 

 circumstances the earth takes nearly the whole of the water, 

 leaving the sand too dry (unless a state of saturation of the 

 earth is approached) for the proper support of vegetable growth. 

 Hence the difference in the behaviour of trees in sand, when 

 that sand is in contact with earth instead of being isolated 

 and kept moist, as it is in a pot. 



DISTRIBUTION OF NEW ROOTS 



This section may be concluded with a more detailed reference 

 to an inquiry into the formation of -roots by transplanted trees 

 which was omitted from its proper place, in order not to interfere 

 with the general account of the conditions governing the planting 

 of trees. 



The distribution of new rootlets forming on trees was ex- 

 amined by planting 150 young apples, pears and plums, lifting 

 a certain number of them at monthly intervals between April 

 and November, and counting the rootlets which had formed 

 (a) within a quarter of an inch of the root-ends, (b) on the main 

 body of the old roots, and (c) on the stems. Out of every 

 100 rootlets (16,000 were counted) 15, 71 and 14 originated 

 from these three loci, respectively (XV, 21), and such propor- 

 tions remained fairly constant throughout the eight months. 

 In another series, carried out three years later, where apples 

 on the paradise stock alone were examined, the distribution 

 was 41, 24 and 35 per cent., respectively. The high value in 

 this case for the rootlets forming from near the ends of the 

 old roots was partially accounted for by a length of half an 

 inch, instead of a quarter of an inch, from the ends having been 

 selected for the count; but that did not explain the whole of 

 the difference in the two series, and left much to be attributed 

 to differences in the season and in the individuality of the 



