74 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



In another of one hundred rows they are 100 : 88-4. 



There seems, therefore, no doubt that the end plant has a con- 

 siderable advantage over others in the row. 



Reference to the plan will show that of the end plants in the planting 

 series there referred to, sixteen, i.e. one at the exposed corner of each 

 plot (marked X on the plan,,fig. 21) was open on two sides, while the 

 other thirty-two (E on plan) were open on but one. This extra 

 exposure made its influence felt, for the sixteen plants gave a total 

 yield of 46 lb. 7 oz., the thirty-two only 61 lb. 5 oz., i.e. 100 : 66 in 

 favour of the corner plants. The average yield of these corner plants 

 was also much better than that of the other plants in the outer row as 

 100 : 79, and compared with the inner plants on the plots as 100 : 57. 



The best " place " is therefore the corner site (X), next a place in 

 the outer row (0), next a place at the end of one of the inner rows (E), 

 and the least favourable an inner place (I, fig. 21). 



Place is therefore an important factor in the yield of potatos, and 

 it is clearly necessary in making comparisons between yields on differ- 

 ent plots to ensure that the exposures of the plants on the comparable 

 plots are exactly the same. Where, for instance, variety trials are 

 made and comparisons desired between crops, not only must the 

 distances between the rows be the same and the distances between 

 the plants in the rows, but the outer row must be discarded. In all 

 the trials at Wisley an outer row is planted which does not enter into 

 the trial at all. In some cases it is necessary, in order to secure equal 

 exposure for all the plants in an experimental planting, to discard the 

 end plants of the rows as well, but this is not usually necessary when 

 in a variety trial the whole length of a row consists of one variety. 



XXXIV.— On Double Stocks. 



By P. J. Jaramillo and F. J. Chittenden, F.L.S., V.M.H. 



The all but universal wish of the cultivator of stocks to plant out only 

 those that will give double flowers has led to a large number of recom- 

 mendations as to their raising and selection. Miss E. R. Saunders 

 has given a summary of the " various methods which have been 

 advocated in the past as leading to the production of doubles among 

 Stocks, but which have proved on investigation to be without effect," 

 in this Journal, vol. xl. pp. 459-465. Having dismissed all thirteen 

 methods as failing of their purpose, she suggests that the high percent- 

 ages often quoted may be due not to the methods consciously set out to 

 be followed, but to the unconscious selection of the most vigorous 

 plants at transplanting time. She subjected this suggestion to in- 

 vestigation and concluded * " that doubles on the whole develop 



" A Suggested Explanation of the Abnormally High Records of Doubles 

 quoted by Growers of Stocks (Malthiola)." — Jour, of Genetics, 5 (i9 I 5) 

 PP. I37-M3- 



