214 REPORT OF THE CONFERENCE ON GENETICS. 
Other writers, however, have denied that this belief has any founda- 
tion in fact, and for this reason | thought a comparison of the colours of 
hybrids with those of their parents, in order to test the question whether 
any rule of influence of pollen or seed parent on the colours of the hybrid 
could be stated, would be of interest to this Conference. 
There are at least three reasons, in addition to the contradictions that 
have arisen, why this comparison seemed desirable. 
(1) The importance of a knowledge of the laws governing inheritance 
from a practical a$ well as from a scientific standpoint. 
(2) The case of reciprocal crosses ; and 
(3) The results of the recent investigations into the Mendelian laws 
of inheritance. 
The first point needs not to be enlarged upon ; its truth is self-evident. 
The second, concerning reciprocal crosses, presents itself as a contradiction 
to the statement that the pollen parent exerts the greater influence on the 
colouring of the hybrid, a contradiction which, one would think, should 
have shown what little reliance could be placed upon rules that seek to 
_assign certain influences exclusively to the male or the female parent, for 
it was shown long ago that the results of reciprocal crosses vary very 
little from one another. M. Naudin, in describing some hybrids between 
Datura ferox and D. levis, says the offspring of this reciprocal cross 
attained ‘‘ the most complete development, and were so perfectly like each 
other that the two sets might easily have been regarded as one... . 
This is a new confirmation of what I have already announced (‘ Comptes 
Rendus de I’ Acad. des Sci.,’ 1862), that there is not a sensible difference 
between reciprocal hybrids of two species, and that in the first generation 
the hybrids of the same origin resemble each other as much as individuals 
of pure species from the same sowing.’ * Darwin, too, arrived at the 
same conclusion, for he writes : ‘‘ Hybrids raised from reciprocal crosses . . . 
rarely differ in external characters.” T 
Col. Trevor Clarke found that the reciprocal crosses of Begonia Dreger 
and B. heracleifolia and of B. cinnabarina and B. Pearcei each produced 
plants which scarcely differed from one another and instances of this might 
be easily multiplied. 
The third point is again one in which doubt is cast upon the belief 
that the male parent has a prepotent influence in determining the 
colour of the flowers, and the law of dominance, which is the first of the 
Mendelian laws, has received almost sufficient confirmation, I think, to 
show that we must look to special characters to impress themselves upon 
the hybrid, whether these characters belong to the male or to the female. 
It has long been known that certain characters are dominant over others, 
although attention has not been drawn to the fact so clearly as since the 
awakening of interest in the laws of inheritance, especially as propounded 
by Mendel, owing largely, in English-speaking countries at least, to the 
efforts of the President of this Conference. 
Gaertner found that “some species of the same genus have a remark- 
able power of impressing their likeness upon their hybrid offspring,’ and 
again, ‘there are certain hybrids which, instead of having, as is usual, an 
* Naudin, Jown. R.H.S. 1866, p. 
t Darwin, Origin of Species, 6th an p. 379 
