ON THE ORIGIN OF NEW SPECIES 
time and dying; or separating where united; or 
bearing one or two crops of fruit and then 
suddenly blighting; or separating after years of 
growth up to complete congeniality. So it is 
in crossing,—all grades of hybridity are to be 
found. Crossed plants generally have the 
characteristics of both parents combined, yet 
sometimes show their parental influences on 
one side, producing uncertain results in the 
first generation. In the second and succeeding 
generations these cross-bred seedlings usually 
break away into endless forms and combi- 
nations, sometimes reverting to some strange 
ancestral form which existed in the dim past. 
Or the break may not occur until after many 
generations. But when once the old, persist- 
ent type is broken up, the road is open. for 
advances in any useful direction. Sometimes 
hybridized or crossed seedlings show consider- 
able, or even great, variation for weeks; or 
they may show no change in foliage or growth 
from one or the other parent form until 
nearly ready to bloom or bear fruit, when 
they suddenly change in foliage, growth, char- 
acter and general appearance.” 
This question of the origin of new species 
219 
