484 BOTANICAL GAZETTE [DECEMBER 



of the inheritance of unit characters in maize, and have succeeded in clear- 

 ing up most of the difficulties met by CORRENS and LOCK, and simply by the 

 expedient of applying a strictly individual analysis, instead of permitting 

 pollinations from a number of individuals possessing the same characteristics. 

 Only a few of the more striking results can be mentioned. There are two 

 independent genes for yellow endosperm color, giving F 2 ratios 3 : i and 15:1. 

 These are so related as respects dominance that the intensity of the yellow 

 color agrees approximately with the actual number of Y genes present, i.e., 

 the color is most intense in seeds having both genes homozygous, less intense 

 when one gene is homozygous and the other heterozygous, still less intense when 

 both are heterozygous or when either is absent and the other homozygous, etc. 

 This situation results in a distribution of individuals in the form of the probable 

 error curve, and is therefore superficially like that of fluctuating variations, 

 from which it differs however in that the different grades are inherited. In 

 another paper the senior author 20 makes use of these facts in extending Men- 

 delian theory to include variation that is apparently continuous. In the 

 purple aleurone color, EAST and HAYES find no less than four independent 

 genes involved in different varieties, a full purple color requiring the simulta- 

 neous presence of both P and C, a full red color the presence of R and C. In 

 the absence of C, both P and R are capable of producing some pigment, giv- 

 ing "particolored" seeds. In addition to these three genes, there was found 

 in a cross between Tom Thumb pop corn and Black Mexican sweet corn, a 

 factor which partially or wholly inhibited the production of the purple aleurone 

 color. This inhibitor or "dominant white" is strictly normal in its hereditary 

 behavior, and its presence in some of LOCK'S strains undoubtedly accounts 

 for that investigator's aberrant results. In pericarp colors the authors recog- 

 nize five independent red-producing genes, R x the ordinary red of "red" 

 maize, R 2 the striped red of "calico corn," R 3 a dirty red most abundant at 

 the base of the grains and apparently completely coupled with red silks, R 4 and 

 R s a rose red which reaches full development only on exposure to the sunlight. 

 The red cob-color is a simple Mendelian dominant, independent of pericarp 

 color. While starchiness is an endosperm character and shows xenia, the 

 quality of the starch, whether flinty or floury, is a "plant character," and 

 affects all the grains of an ear. Crosses between flint and dent varieties show 

 undoubted segregation with the flint character recessive, but there are prob- 

 ably several genes involved, and the results are obscured by physiological 

 correlation. Further evidence is given that size characters, such as height 

 of stalk, length of ear, and size of grains, segregate normally in the F 2 . Several 

 abnormalities are mentioned, dwarfness, striped leaves, split and furrowed 

 cobs, branched ears, and hermaphrodite flowers. With exception of the last, 

 these characters are thought to be inherited in Mendelian fashion, though the 





20 EAST, E. M., A Mendelian interpretation of variation that is apparently con- 

 tinuous. Amer. Nat. 44:65-82. 1910. 



