Studies on the Variability and Heritability 
of Pigmentation in Oenothera. ER: 
By R. R. Gates, St. Louis. NEW YORK 
BOTANICAL 
Introduction. GARDEN. 
This paper is a summary of certain observations made during the 
last four years on the variation and inheritance of the red pigment, 
anthocyan, in Oenothera. The petals in nearly all the species are 
constantly yellow, though varying in their depth of shade in different 
forms. These studies concern the development of the red color pattern, 
which occurs particularly on the calyx, in many forms, but which may 
also appear in various other parts of the plant. In most cases these 
quantitative differences in pigmentation appear to be non-heritable, 
but one striking case in which there is strict inheritance of an extreme 
amount of pigmentation, will be described. A series of crosses between 
this extreme variant, or mutant, and other forms has also yielded 
interesting results. 
Oenothera rubrinervis, one of the mutants from O. Lamarckiana, 
is the form which has been used for much of this study, because one 
of the conspicuous differences between O. rubrinervis and its parent is 
the presence, usually, though not invariably, of an increased amount 
of anthocyan, particularly on the sepals and the rosette leaves. 
A preliminary study of the intra-individual variation of the red 
color-pattern on the buds, and of other characters, particularly of 
O. rubrinervis, was first made in 1907. Certain general features of 
this variability may now be stated. 
It is a commonplace of observation that no two individual plants 
nor organs of the same plant are identical. Thus no two leaves or 
internodes of an Oenothera plant are just alike in any particular. Not 
only is this the case, but in any individual there are tendencies of 
change in every organ in successive members of a series. The varia- 
tions in nearly all the organs of an individual plant are of this 
Induktive Abstammungs- und Vererbungslehre. IV. 22 
