THE OCCURRENCE AND INHERITANCE OF SEX INTERGRADATION IN PLANTS

Abstract

In a previous paper (1919) I have called attention to sex intergradation in Mercurialis annua in both male and female cultures.It is my purpose here to discuss the general question of sex intergrades as they occur in the flowering plants.This discussion is based in a large measure upon the results: reported in the paper mentioned above.There can be no question from the data at hand that sex in Mercurialis.is a fluctuating rather than a fixed character expressing itself in a wide range of sex intergrades, including as the extremes some pure male and some pure female plants and midway between the extremes highly fertile monoecious.forms.'The sex intergrades here are all highly and equally fertile, and no suspicion of abnormality or of pathological conditions can attach to them.That there is a tendency to pure dioecism seems highly probable, but the transition from hermaphroditism is still represented by all possible gradations, showing most convincingly that theories of sex determination based on the segregation of fixed unit factors can have no significance for such:types. SEX INTERGRADES~ Goldschmidt (1916a@) reports in a preliminary paper upon the sex ratios.in crosses between the European and Japanese races of the gypsy moth, Lymantria dispar.He obtains various gradations in the sexual condition