Pigments of the Mendelian Color Types in Maize: Isoquercitrin from Brown- Husked. Maize.*

At Cornell University, Emerson has been the leader in an important series of genetical investigations of maize, in which the Mendelian factorial composition of many color varieties has been established. In a recent memoir1 he has dealt especially with what he terms plant colors; i.e., colors due to pigments (otherthan those of the chloroplasts) whichare commonly seen in the husks, the staminate inflorescence, the foliage generally, and the stem. Of such plant colors he has established the genetical relations of six main types as follows: (1) purple, (2) sun red, (3) dilute purple, (4) dilute sun red, (5) brown, (6) green. In a former paper in this Journal* we have pointed out the importance of chemical studies of such color series as this in which the genetical factorial analysis has been made. Only by the chemical investigation of genetically known material may we hope to come to any satisfactory understanding of the meaning of the Mendelian analysis, and of the actual operation of the factors which in such an analysis are known as symbols. The plant color series in maize immediately suggests a parallelism with similarly related varieties of other plants in which flower color (due to cell sap pigments of the flavonol and anthocyanin groups) varies from white to various shades of yellow, red, and purple. Such a parallelism has already been confirmed* by the isolation of a quercetin glucoside from