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Scientific Proceedings, Royal Dublin Society. 



commenced about five weeks after planting, were made from the apical bud to an 

 ink-mark situated a couple of centimetres above the ground. A further period of 

 ten weeks elapsed before the final measurements, when the plants were dug up 

 and the tuberous portions of the roots and the stems weighed. A ring, approxi- 

 mately half an inch wide, of the extra-xyliary tissues immediately above the ink- 

 marks was removed from the stems of alternate plants. The ringing operation 

 was done between the eleventh and twelfth weeks after the commencement of 

 the measurements. The results reported in Table 1 show the rate at which the 

 stem elongated in the two groups. The weights of the tuberous portions of the 

 roots will be found in Table 2. In making the weight determinations of the stem, 

 which are also recorded in Table 2, all the leaves were removed, and the stem cut 

 into three equal segments, and then weighed. The reproductive phase of develop- 

 ment was not initiated during the course of the experiment. 



Table 1. 

 Showing rate at which stem elongated in ringed and unringed plants. 

 The figures in the body of the table show the height in centimetres at various dates. 



