45 2 Solms-L cutback- — On the Fructification 
times gives rise to an infinite number of different but always 
analogous results, because the substratum to be modified 
in each case has meanwhile been essentially changed. I 
have no doubt that we shall in time be able to refer other 
groups of phenomena also to common operative principles 
of adaptation. 
If this may be assumed, it is clear that Saporta’s Pro- 
angiosperms cannot represent a well-defined group in the 
genetic system, but must consist of the members of 
different analogous developmental series, which have under- 
gone evolution of a similar kind. The number of ancestral 
forms which pass through such a proangiospermous stage may 
then be very large ; their other characters may be very dif- 
ferent. How many of them, whether one or several, and 
which, have become the parents of our modern Angiosperms, 
may at present be beyond our conception. In the many 
phylogenetic speculations which have sought to explain the 
mutual relations of different classes in the vegetable kingdom, 
the botanical authors have as a rule disregarded or incorrectly 
applied the results of palaeophytology. It is much to be 
desired that these results should be more highly valued in the 
future. For this study, though now fragmentary and incom- 
plete, is much better suited than that of the classification of 
living plants to throw light upon the enormous difficulties 
which stand in the way of all attempts of the kind, and thus 
to warn us at every moment against precipitation, and to bid 
us be cautious. 
