90 
ANNE M. LUTZ 
to prove that 0. nanella only, invariably results from this cross; and 
finally, since only 27 offspring were derived from the later mutant, 
selfed, it is clear that we are not justified in formulating definite 
conclusions concerning its behavior. 
The behavior of O. lata rubricalyx is somewhat unique. If all of 
the offspring of the mutant, selfed, had 14 chromosomes, as Gates 
thinks probable, this fact would indicate that all of the male and 
female cells produced which were capable of functioning, had 7 chro- 
mosomes. This is further indicated by the fact that although Gates 
crossed the mutant both ways with several other forms, "the offspring 
(few in number) which developed proved to be all of 14-chromosome 
types." He does not state whether the several forms employed in 
these crosses were 14- or 15-chromosome plants, but the results in- 
dicate that only 9 7 + d^7 unions occurred in every case, or at least 
that only seeds resulting from these unions germinated in the time 
allowed them. Of especial interest is the fact that the 14-chromosome 
offspring of this plant were intermediate between rubricalyx and grandi- 
flora (the grandparents). Would the mutant behave differently if 
produced by rubricalyx, selfed? Is this precise type ever produced 
by rubricalyx? 
In the case of 0. albida, all of the cells of one sex appear to contain 
7 chromosomes and all of the other 8, since de Vries obtained albida 
offspring only from this form, selfed. 
Thus, in addition to 0. lata, the records show that a certain number 
• — commonly more than half — of the offspring derived from selfed 
0. bipartita, 0. scintillans, 0. sublinearis and almost all of those ob- 
tained from selfed elliptica (the evidence is not clear in regard to 0. 
semilata Gates) were 14-chromosome plants and that all of them, or 
all but a few mutants (providing the oblonga offspring of 0. scintillans 
had 15 chromosomes), were 0. LamarckianaP Hence the evidence 
as it now stands indicates that all but relatively few of the 7-chromo- 
some male and female gametes of these plants (providing scintillans 
and sublinearis are 15-chromosome forms) are bearers of Lamarckiana 
characters'^ and that the mutant characters of the 15-chromosome 
It is probable that the list of forms which produce large numbers of O. Lam- 
arckiana when selfed, might be extended to include many other direct and indirect 
15-chromosome mutant derivatives of O. Lamarckiana, but not all; O. nanella lata 
and 0. ruhrinervis lata may be suggested, among others, as probable exceptions. 
33 The evidence indicates that all of the 7-chromosome gametes of one sex pro- 
duced by 0. elliptica and all but comparatively few of the opposite sex, which are 
