R. N. Salaman 15 



time " Reading Russet " texture was united to intermediate shape, 

 which might possibly be an error of observation. 



These observations demonstrate at least that such fleeting and 

 difficult characters as leaf shape and texture in the potato segregate 

 in the sexual generation. 



This year^ a fresh F- family of this cross is being raised, and close 

 attention will be paid to their foliage character. 



The Shape of the Tubers. 



No character seemed at first sight more elusive and less likely of 

 solution in respect to its heredity than that of shape. Whenever I 

 spoke to experts I was told that from the best " kidney " types you 

 could pick out "rounds," and that exhibitors had won prizes both for 

 " rounds " and for " kidneys " from one and the same potato. 



East (5) notes four cases where originally "long" tubered varieties 

 produced as bud sports rounded tubers; in two cases these "round" 

 tubers reproduced themselves vegetatively true to " roundness," while 

 the other two relapsed in the following season. 



The oval varieties he notes as producing on single plants entire 

 crops of very elongated tubers, which however did not grow true in 

 subsequent years. 



My observations would lead me to think that these bud sports in 

 " kidney " and oval potatoes are quite common and are to be explained 

 by their heterozygous composition as regards "roundness." 



A frequent cause of trouble in dealing with the shapes of tubers is 

 the nomenclature. The terms used to describe the different shapes are 

 suflScient for the purpose of the gardener, but they connote no scientific 

 accuracy. 



Where the cylindrical potato ends and the kidney begins, where 

 the latter ceases and the " pebble " starts, and where both merge 

 into the round is a problem which it would be hopeless to attempt to 

 solve by the mere classification of tubers. 



It is only by the isolation of a type and its fixation as pure when 

 bred sexually that the problem can be solved. 



In describing the shape of a potato, two points can be regarded as 



' In 1910 out of 71 F- seedlings on Aug. 3rd 6 showed the " Fir Apple " twist, on 

 Aug. 23rd 14 had developed it. 



