Nilsson-Ehle was the first to show that duplicate and triplicate factors for red are present in certain strains of wheat. He found, moreover, that the same strain may be in one case monomerous and in another case dimerous for this character; and that while, for example, Grenadier wheat possessed three independent units for red, Extra-Squarehead possessed only one. The origin of the original "factor" for red may be accounted for in the wheats as in Œnothera rubricalyx, through the chemical transformation of one chromosome or a pair of homologous chromosomes. The duplicate condition for the character R may have arisen (1) through a chemical mutation in a second pair of chromosomes, (2) through a re-mating of the chromosomes (RR) forming a homozygous pair. The latter method is for various reasons the more probable.Although the original Œnothera rubricalyx was a monohybrid and continued so for at least two generations, yet in subsequent generations involved in crosses with Œ. grandiflora, 15:1 or di-hybrid ra...