MONOGRAPH OF THE GENUS STROPHIA. 
9 
As would naturally be expected in so plastic a genus, indications 
of the probable appearance of species very frequently occur. In such 
groups there is often strong inclination to assume certain characters, 
but on account of frequent gradation, through both reversion and direct 
hybridization, no absolutely fixed characters can be found. As all 
gradations occur between a group that might, at first sight, appear 
strongly marked enough to be considered as a sub-species, and what is 
most undeniably individual variation, I have not ventured to name these 
groups, not knowing where to draw the line, but I have always mentioned 
them, stating their peculiarities, The differences which now render 
these forms conspicuous, may increase and form a species with the in- 
dividual characters prominent, or the form may revert to the original 
species and so become absorbed, or again, it may assume under some 
changing circumstances, totally different characters, acquiring a final 
specific form, utterly at variance from what now appears probable. 
For remarks on origin of the genus, evolution of species, and rela- 
tionship to allied genera, see General Conclusions. 
