through Self-adaptation to a Moist or Aquatic Habit . 743 
19. Isolation and Natural Selection. 
It may be observed that I have said nothing about ‘ Isolation ’ and 
c Natural Selection ’. Instead of the former, I prefer to say a new environ¬ 
ment , however the seeds may have happened to get into it. With regard 
to the latter phrase, Darwin described it as being only metaphorical. 1 
I follow his later ecological explanation of evolution ; for I find that 
in all cases, if a quantity of seeds germinate and grow under new conditions 
sufficient to cause them to vary, they all vary alike , i. e. what he called 
‘ definitely ’, just as Darwin said : ‘ There can be little doubt that the 
tendency [i. e. response] to vary in the same manner has often been so 
strong, that all the individuals of the same species have been similarly 
modified without the aid of any form of selection.’ 2 
20. Conclusion. 
Miss Sargant concludes her long and interesting paper on the ‘ Recon¬ 
struction of a Race of Primitive Angiosperms ’ as follows :—‘ The hypotheses 
which have been considered . . . have led to two phylogenetic schemes only, 
which attempt to explain the evolution of Monocotyledons from Dicotyle¬ 
dons from a common ancestor. The first is that of Professor G. Henslow. 
The second is the fusion (of the two cotyledons) hypothesis.’ 
If the blades only be thought to be ‘fused’ then there is no proof of 
such being the case, as shown by Ranunculus Ficaria . But I understand 
Miss Sargant to mean by ‘.cotyledons ’ solely the strand or the vascular 
bundle of the lost cotyledon to be retained in the sheath and petiole of the 
one present; as she has shown to be the case in Anemarrhena. 
All I would maintain is that the strand is the last relic of the cotyledon 
which has been otherwise totally arrested by water. 
The reader will now probably have read enough to perceive, first, that 
there is an immense number of coi?icidences which occur among aquatic 
plants of both classes. Secondly , that all terrestrial Monocotyledons exhibit 
the same coincidences, but coupled with re-adaptations for living in air. 
These coincidences afford an abundance of inductive evidence of their having 
had a common origin in ancestral hygrophytes or hydrophytes among 
Dicotyledons. 
Thirdly , experimental verification now covers the peculiarities of the 
roots, stems, and leaves of Monocotyledons ; proving that water was the 
actual source of what Darwin called ‘ the direct action of the conditions 
of life ’, to which the plant responds. Such acquired, aquatic, structural 
1 Origin, &c., 6th ed., p. 65, 
2 Ibid., p. 72. The paragraph containing this quotation is not in the first edition. 
