Between Drosera filiformis and D. intermedia. 97 
demonstrates that in this, as in some other hybrids studied, 
certain parts or organs tend more toward one parent than 
another. The balance of development throughout in the 
present case is evidently toward D. intermedia. Thus, in the 
relative size of the tentacular hair heads, in the amount of 
thickening of the indurated cortex cells, in the greatly reduced 
size of the glandular hairs of the sepals as inherited from D. 
filiformis, and in the color and size of the flowers, there is a 
decided preponderance in morphological detail of D. ixtermedia 
over the other parent, or the former exercises a certain swamp- 
ing effect on the growth vigor handed down from the latter 
parent. This is all the more remarkable when one considers 
that the apparently prepotent parent is the smaller and more 
delicate species. Until facts can be obtained on which to base 
an exact explanation we can at best merely theorize. But I 
would again advance as a highly probable hypothesis the view 
given in my earlier paper, viz., that the sex cells of the pollen 
grain or of the ovule may have attained to a greater size in 
the smaller species, and may have contained a larger amount 
of hereditary chromatic substance. In the graft hybrid 
Cytisus Adami admirable and direct evidence is afforded of a 
much smaller species, Cytsus purpureus, having greatly larger 
nuclei and more chromatin apparently in its epidermal cells 
than the larger species, C. Laburnum, which has contributed 
with it to the formation of the graft hybrid. The graft hybrid 
itself closely resembles the smaller species in the size, appear- 
ance and relation to stains of its epidermal nuclei; not to 
mention other and more evident characters. A like condition 
may exist in the hybrid and parent forms of Drosera, even 
though scarcely, if at all, discernible under the microscope. 
It is hoped that a careful study can yet be made of this fea- 
ture with the material now under cultivation. 
The phenomenon which the writer termed bisexual hybridity 
receives several striking exemplifications. Where two more 
or less diverse growths have occurred, one on either parent, 
7 
