92 
ANNE M. LUTZ 
chromosome plants never duplicate the vegetative characters of their 
parents, it is clear that 8+8 (lata 8 + lata 8, for example) could not 
produce an individual having the same vegetative characters as the 15- 
chromosome parent}^ 
In view of the fact that when certain 15-chromosome forms are 
selfed, the parental mutant type appears to be reproduced by 8 + 7, 
and never by 8 +8, unions, one may ask whether we are not justified 
in asserting that the 7-chromosome cells are as truly transmitters of 
the mutant characters as the 8-; it seems that they are not, for the 
22-chromosome offspring of 0. lata X 0. gigas, which presumably 
result from 9 8 + 6^14 unions, suggest lata-gigas characters, while 
2i-chromosome hybrids, which doubtless result from 9 7 + cfi4 
unions, suggest Lamar ckiana- gigas combinations. Since the latter 
bear no trace of lata characters, it is clear that these are transmitted 
through the 8-, and not through the 7-chromosome gametes. 
If 7- and 8-chromosome male and female gametes were produced 
in equal numbers, all capable of functioning in union with 7- and 8- 
chromosome cells of the opposite sex, we would expect a selfed 15- 
chromosome form to produce 14-, 15- and i6-chromosome offspring in 
the ratio of 1:2:1. How, then, shall we explain the fact that the 
number of 14-chromosome offspring produced usually (not invariably, 
as we have seen) exceeds the number of 15-, while i6-chromosome 
forms are almost unknown in such cultures? How shall we explain 
the fact that Fi cultures derived from 15-chromosome forms pollinated 
by 14- usually contain many more 14- than 15-chromosome plants 
I. In the first place, it will be recalled that no evidence has been 
brought forward to show that 8-chromosome male gametes, capable 
It is quite probable, however, that lata-Mke mutants may result from lata 8 + 
lata 8. 
26 After the manuscript for this report had left the writer's hands, an important 
contribution from de Vries appeared, entitled " New dimorphic mutants of the 
Oenotheras " (Bot. Gaz. 62: 249-280, Oct., 1916). In this report de Vries has shown 
that 0. cana, which is probably a 15-chromosome form, produces O. cana and 0. 
Lamarckiana when selfed, but that a larger percentage of the offspring duplicate the 
characters of the mutant parent when a biennial, than when an annual, plant is em- 
ployed. This fact demonstrates, as he states, that the behavior of 0. cana is largely 
dependent upon the vigor of the individual employed. De Vries believes that this 
is true of other dimorphic mutants, since he had earlier demonstrated this difference 
in the behavior of annual and biennal scintillans. The bearing of these important 
facts upon the statements which are included under the heads of i, 2 and 3 above, 
will be discussed in a later publication. 
