i92o] COULTER— A LEV RONE COLOR 415 



the latter, in all cases but one, revealed PprrCc. In this one case 

 the individual produced by this supposed PprrCc grain was selfed, 

 and gave a ratio of 46 : o : 36. This is a perfect 9:0:7 ratio, such as 

 would be produced by PPRrCc, but such a formula is out of the 

 question in view of the history behind the ear. The obvious but 

 heterodox suggestion is that some unusual condition is present, 

 which, together with both P and C, results in purple aleurone; while 

 with C alone it gives, not red, but colorless. 



That this is a pathological case is suggested by two facts: 

 (1) practically all the grains on this ear had their pericarps split 

 irregularly, an unusual condition; (2) when planted, they germi- 

 nated very slowly (or not at all), giving 3-inch plants at the time 

 that all the neighboring rows had attained 3 or 4 feet; by harvest 

 time a few small tassels had just appeared, but no silks. 



Mottling 



Emerson (loc. cit.) has described the following situation iu 

 certain of his families. When the R factor enters the cross with 

 the male parent only, a mottled aleurone results, while in all other 

 cases a solid aleurone color is produced. Thus, RRccXrrCC gives 

 100 per cent solid red; rrCCxRRcc gives 100 per cent mottled 

 red; RRCCxRRcc gives 100 per cent solid red; RrCC selfed 

 gives 50 per cent solid red, 25 per cent mottled red, and 25 per cent 

 colorless. 



The writer wishes to express his appreciation to Emerson for 

 providing material of the well known C tester and R tester. These 

 races behaved with considerable regularity, for crosses between 

 them consistently yielded 100 per cent solid purple grains when 

 R tester was used as the male parent (PPRRccXPPrrCC), and 

 100 per cent mottled grains when C tester was used as the male 

 parent (PPrrCCxPPRRcc). 



Splashed purple grains, recognized by East {loc. cit.) in most, but 

 not all, of his families, were doubtless due to the same phenomenon. 

 In the particular material of East's which was furnished, however, 

 nothing of the sort could be identified, even in the very numerous 

 cases in which the R factor came in with the male parent only. It 

 was felt, therefore, that crosses between the material from Emerson 



