342 Gates. 
originated by a germinal variation from O. rubrinervis, and it breeds 
true except for certain individuals which revert to O. rubrinervis. 
It differs from O. rubrinervis only in the quantity of pigment pro- 
duced, but since it fluctuates about a new center of stability and 
shows no tendency to produce individuals bridging the gap between 
it and O. rubrinervis, it must be considered a separate form and must 
be removed from the class of ordinary fluctuating variations. Its 
hereditary behavior will be discussed later in this paper. 
Usually the yellowish marginal lines of the sepals in O. rubrinervis 
are broader than the median ridge. Occasionally, however, by an 
increase in the width of the red area, the former become as narrow as 
the latter (fig. 7). Although there is a considerable latitude of variation 
among the different flowers of an individual, one type or stage of color 
pattern usually predominates, i. e. a statistical examination will show, 
with sufficiently large numbers of flowers, a single mode for éach in- 
dividual, except that in certain cases the flowers of a sideshoot may 
have a different mode from those of the main stem and branches. 
The extent only of the red color pattern has been subjected to 
statistical study, but a number of other color variations occur in the 
bud. The depth of shade of the red color is very variable in O. rubri- 
nervis. The commonest shade is a bright red (type 5) but frequently 
a majority of the buds of an individual show a much paler shade 
(type 4), and all stages between it and type 5 may occur. This paler 
color may appear with any stage of reduction of the color pattern. 
The red is also sometimes of a somewhat deeper shade, approaching 
a maroon. The amount of yellow pigment present in the sepals also 
varies, so that the non-red portion of the bud may be various shades 
of greenish (type 6) or yellowish (type 5). Occasionally the buds 
may have a peculiar shining or varnished appearance. The various 
combinations and degrees of these variations in the same bud gives 
an infinite variety of conditions. 
After fertilization, when the flowers of O. rubrinervis are wilting 
and about to fall, the hypanthium changes in color from yellowish 
green to pale reddish. The bases of the wilted petals also acquire 
a reddish tinge, and the color disappears from the sepals. This change 
in color of the petals on wilting occurs in several of the mutants and 
is more marked in some other species of Oenothera, which acquire a 
deep orange shade. 
The few observations made on the ontogeny of the color pattern 
in O. rubrinervis indicate that the red appears in the full color pattern 
