No. 642] NATURE OF BUD VARIATIONS 



67 



is, therefore, as truly a lieterozygote as if it had arisen 

 through hybridization of green and variegated strains. 



Self-colored branches on variegated-flowered plants of 

 Mirabilis usually do not transmit the self-color character 

 to their seed progenies in greater percentages than do 

 variegated-flowered branches of the same plants. They 

 are thought by Correns to be fundamentally of the same 

 nature as the green branches of variegated-leaved plants, 

 their failure to transmit the self -color character being due 

 presumably to the accident that the mutation occurs in 

 epidermal cells from which no gametes arise. The fre- 

 quent occurrence of self-colored plants in seed progenies 

 both of self-colored and of variegated flowers is consid- 

 ered evidence of their origin as vegetative rather than as 

 gametic mutations, their failure of expression in the 

 soma being thought due to their origin in sub-epidermal 

 cells in which these flower colors do not develop. 



Studies of variations in variegated pericarp of maize 

 by myself (Emerson, 1914, 1917) and by Anderson, 

 Eyster, and Demerec,^ involve practically the same results 

 as those so far reported in investigations of other species 

 and afford in addition quantitative data on certain as- 

 pects of the somatic-mutation problem not included in 

 other investigations. The genes for variegated pericarp 

 have been shown to belong to a comparatively large series 

 of multiple allelomorphs including those for colorlessness 

 (white seeds), self color of different intensities, and cer- 

 tain definite color patterns of both the pericarp of the 

 seeds and the glumes and palefB of the cobs. Variegation 

 is known to be a simple recessive to self color and a domi- 

 nant to white. 



Self-colored seeds whether occurring singly or in 

 groups in variegated ears produce progenies consisting 

 of approximately 50 per cent, self-colored ears, the other 

 60 per cent, being either all variegated or all white de- 

 pending on whether the parent was homozygous varie- 

 gated, V V, or heterozygous variegated, V W, from a pre- 

 vious cross with white. Seeds that are less than wholly 

 self colored throw a correspondingly smaller per cent, of 



