Active Causes of Organic Evolution 



185 



nucleus from another species or even genus of plant or animal, 

 and so to build up a dual organism that may, as the writer 

 has demonstrated (63 fassiin), either blend exactly all of the 

 parental peculiarities, or exhibit these as distinct morphological 

 structures side by ^ide with each other, as in the accompanying 

 illustrations, where the large honey gland of one parent species 

 of liliaceous plant, Lapageria (Fig. 2, a, b, and c), is entirely 

 absent in the allied genus Philesia, but is reproduced of about 

 half size in the hybrid "genus" Philageria, developed under 

 cultivation. The writer has cited or illustrated various simi- 

 lar cases amongst flowering plants. 



Fig. 2 — Long. sect, through base of sepal of (a) Philesia, (b) Philagcria the 

 hybrid, (c) Lapageria. gl. gland. 



If then it be asked wherein one species can be surely sep- 

 arated from another in hereditary relation, we would reply 

 that, if by any environal stimuli some one or more characters 

 or responses to energy be so replaced or modified by energizing 

 action of another kind or type that the original character or 

 response fails to reappear in the immediate descendants, while 

 the new kind or type does, a new species results. But this 



