Between Drosera filiformis afid 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. 

 filifonnis, and in the color and size of the flowers, there is a 

 decided preponderance in morphological detail of D. intermedia 

 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 

 Cytisns Adauii admirable and direct evidence is afforded of a 

 much smaller species, Cytisns pnrpnreus, having greatly larger 

 nuclei and more chromatin apparently in its epidermal cells 

 than the larger species, C. Labiirman, 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 



