5) 
colonies. In fact, there is serious reason to believe that such a 
mutant group would be handicapped. Morgan and his co- 
workers and many other investigators of inheritance and muta- 
tion phenomena have repeatedly called attention to the strange 
fact that mutations for the most part are weak or less fitted to 
cope with their environment as compared with the more vigorous 
common wild types. The centuries involved in perfecting such 
organic machines, through the workings of natural selection and 
mutation, have brought about such a degree of adaptation 
between the organism and its surroundings that any change, 
though seemingly slight, may handicap it, particularly in com- 
petition with its ‘‘normal” or wild kindre 
But even supposing no such handicap were involved, and the 
species in which a mutant occurred with ability to tolerate greater 
degrees of cold were resident in the tropics, how would this mu- 
tant’s existence be recognized? So far as the writer can see, under 
present day practices in horticulture, landscape gardening, and 
forestry, the chance of discovering it would be extremely remote. 
Traditionary practice and belief, the propagation of the great 
majority of economic and ornamental herbaceous perennials 
and woody plants by asexual methods (cuttings, crown divisions, 
budding, grafting, bulbs, tubers, etc.), all form obstacles against 
which such a mutant could make itself known only by the 
merest chance. And when collections of seed are gathered in 
such regions for transmission to more temperate climates, the 
collections are from comparatively few individual plants. Hence 
there would be small likelihood of discovering such mutations 
accidentally. 
For some years, the writer has been collecting information on 
the variation, among the individuals of a species, in ability to 
resist various degrees of cold. The problem as it presents itself 
can best be put in the form of a question. Is zt not probable that 
many tropical, sub-tropical, and temperate species give rise, through 
mutation, to individuals or to small groups of individuals much more 
cold-resisting than the individuals of the species as a whole, and that 
these “hardy” mutants remain for the most part unrecognized 
because they occur and grow under conditions where the character in 
question could not be expressed? 
According to current geological beliefs, the climate of the earth 
