330 



EARL S. JOHNSTON 



formation was found to be greater in the Cobbler than in the 

 McCormick. 



It is not difficult to select fairly uniform sprouts from a large 

 number of tubers and the possibility of using these sprouts when 

 cut from their tubers suggested itself as a means of securing uni- 

 form plants. Two sets of sprouts with well developed roots were 

 taken from similar seed pieces and planted in glazed pots con- 

 taining good garden soil. Each set of three plants was watered 

 by means of three Livingston auto-irrigators. 1 In one set, 



Fig. 1. Small tubers growing on cuttings from potato vines. 



sprouts were used whose leaf buds had just begun to grow, while 

 in the other, sprouts with four or five leaves each approximating a 

 square centimeter in area were employed. 



The sprouts were planted on October 17, 1918, and by the 

 following February the plants had grown to maturity and died. 



1 Livingston, B. E., A method of controlling plant moisture. Plant World 

 11:39^40. 1908. 



HaAvkins, Lon A., The porous clay cup for the automatic watering of plants. 

 Plant World 13: 220-227. 1910. 



Livingston, B. E., and Lon A. Hawkins, The water relation between plant and 

 soil. Carnegie Inst. Wash. Pub. 204:5^8. 1915. 



