Tie GENO TY PICAL-RESPONSE OF 
THE PLANT SPECIES TO THE HABITAT 
BY GOTE TURESSON 
INSTITUTE OF GENETICS, AKARP, SWEDEN 
er study of the variability of the plant species in relation to its 
environment, or its habitat, might be pursued along two lines of 
research, viz. the study of the effect of various environmental factors 
upon the individual plant, and the study of the effect of these environ- 
mental factors upon the genotypical composition of a species-popula- 
tion in a certain habitat. The one line of research is primarily a 
study of the modifications of the plant, the other is manifestly a 
study of the hereditary variations. The two groups of variation 
have long ago been dealt with from the point of view of the environ- 
ment, but while the experimental study of the former problem has 
received much attention the latter problem, the hereditary variation 
of wild plants in relation to habitat, has remained experimentally al- 
most unattacked. 
The classical transplantation experiments with Lowland plants in 
Alpine situations performed by Kerner (1891) and Bonnier (1895) 
belong to the important body of facts relating to the modifications 
of plants. The modern study of the problem is particularly connec- 
ted with the names of Kress (1903, 1906) and Gorse (1908, 1913). 
Our knowledge of the power of modification, or rather of the range 
of possible reactions, of the plant when exposed to different environ- 
mental factors has been greatly increased by all this work. Its im- 
portant bearing upon other lines of studies has also been felt, and 
the data obtained through the experimental inquiries into this field 
have been extensively employed when attempts have been made to 
throw light upon less known subjects, especially in the field of 
ecology. This is particularly true of the cases in which the supporters 
- of the theory of the inheritance of acquired characters endeavour to 
find new support for the theory in the increasing mass of data 
obtained (Warmine, 1909, p. 373; WIESNER, 1913, p. 314). That the 
fact of the great »plasticity» of the plant has led to undue generaliza- 
tions even in matters of a less speculative nature will be evident from 
Hereditas III, 15 
