104 Muhlenbergia, Volume 4 
view, and it is the physiologist who has given most emphasis to ~ 
the fundamental importance of experimentation. The ecologist, 
on the other hand, has brought in the rich contributions of field 
observation. . . The ecologist feels that the species problem 
is essentially a field problem, and hence incapable of final set- 
tlement, either in the herbarium or in the laboratory. Yet it is 
the exact methods of the laboratory carried into the field that 
give promise of the solution of the problem of species.” 
“Perhaps no phenomena bring the principles just enunci- 
ated into more clear relief than do those of natural selection. 
Many species must be born that never have an opportunity to 
survive, owing to their lack of adaptation to the surroundings 
in which they originate. The mutants of Oexothera Lamarck- 
zana, though developed under essentially similar conditions, do 
not appear equally adapted to the environment in which they 
first appeared; had they been left to themselves, some mutants 
would have perished, while others (and perhaps especially Oeno- 
thera gigas) might have lived.” 
“One of the noblest aims of ecology is the destruction of 
many of the “species” of our manuals. Where the critical study 
of species is confined to the herbarium, it often happens that 
ecological varieties or habitat forms are given specific rank. 
An excellent instance of this is seen in the case ot Polygonum 
amphibium and P. Hartwrightiz. The latter, which looks won- 
derfully different from the former in herbaria, can be developed 
at will by growing P. amphibium on land instead of in the 
water. Not infrequently a plant may be found on the edge of a 
pond, showing branches in the water that would commonly be 
referred to P. amphibium, and aerial branches that would be re- 
garded as P. Hartwrightit. Bonnier’s classic experiments, 
whereby many alpine plants were shown to be capable of being 
developed into well-known lowland species in a single genera- 
tion, illustrate a phenomenon similar to that exhibited by Poly- 
gonum.” 
