6o6 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



2. Skin injured or not. 

 Skin injured, 

 n Table I. Bad plant 



20 ,, „ 



Skin not injured. 

 26 Table I. Bad plant 



57 

 28 



3i 



65 

 47 



16 Good plant 



Hence bad plants were produced by tubers whether the skin was 

 injured or not. 



And similarly in the case of other characters. 

 Thus it has not been possible to determine any relation between 

 the occurrence of bad plants and certain characteristics of the planted 

 tubers. 



1. The ' President ' produced crops of little value when planted 

 in the open, in light sandy soil at Wisley, in 1912 and 1913. 



2. A greater proportion of bad plants occurred at Wisley in both 

 years than at Wye and Chelsea, in 1911. 



3. The bad plants were dwarfed, with yellowish, blotched foliage 

 and curled or folded leaves, and resembled those I saw in Scotland in 



1910. Some plants failed to grow more than a few inches in height. 



4. In Scotland both good and bad plants set seed ; both good and 

 bad flowered at Wisley, but did not set seed. 



5. The blotched condition of the foliage at Wisley was not due 

 to Macrosporium Solani, this fungus being absent. 



6. The bad plants produced only two or three small tubers each, 

 as at Wye and Chelsea, in 1911. 



7. Tubers from bad plants produced bad plants, as at Chelsea, in 



191 1. One tuber, which has not been included in the Report, placed 

 in a different environment gave rise to a plant with good foliage. 



8. In the greenhouse experiments tubers above the usual size 

 used for planting produced good plants ; tubers below the usual size, 

 bad plants ; tubers of medium size, both good and bad plants. 



9. Both good and bad plants were produced at Wisley from tubers of 

 medium size planted in soils obtained from Dunbar, Wye, and Chelsea. 



10. The tubers are highly variable in shape, eye characters, 

 texture, and kind of skin, but the occurrence of bad plants does not 

 appear to be in any way related to these characters or to injuries to 

 the tubers or sprouts. 



I desire specially to acknowledge the valuable assistance given me 

 in these investigations by Mr. F. J. Chittenden, the Director of the 

 Laboratory, and I also take this opportunity of thanking Professor 

 E. S. Salmon, F.L.S., for carrying out experiments at Wye in 1911 

 and for the tubers and soil mentioned in this Report, Mr. J. W. Hope, 

 Dunbar, Mr. T. A. Scarlett, Edinburgh, and the Curator of the 

 Chelsea Physic Garden, Mr. W. Hales, A.L.S., for their trouble and 

 kindness in sending tubers and soil. 



Summary. 



