112 GOTE TURESSON 
species distributed in that way it appears reasonably safe to conclude 
that the varieties in question each represent the genotypical response 
of the ecospecies to the respective localities. When the development 
of a distinct variety in a distinct locality is thus expressed in terms of 
reaction even such concepts as »selection» and »survival of the fittest» 
also become rather superfluous. 
The reaction products of the above discussed ecospecies have 
been called varieties. That this term gives an inadequate conception 
of the result of the genotypical reaction of an ecospecies to a specific 
habitat is obvious. It is rather arbitrarily used to denominate diffe- 
rent kinds of hereditary deviations from a valid or supposed type and 
cannot therefore be advantageously employed in any ecological sense. 
The term ecotype is proposed here as ecological unit to cover the 
product arising as a result of the genotypical response of an ecospecies 
to a particular habitat. The ecotypes are then the ecological sub-units 
of the ecospecies, while the genotypes are purely Mendelian sub-units 
of the genospecies. A knowledge of the ecology of an ecospecies pre- 
supposes a knowledge of its most important ecotypes, and the know- 
ledge of the ecology of the latter involves primarily a study of the 
variation and the distribution in nature of each of these ecotypes. 
The study of the species along these lines furnishes a necessary 
complement to the Mendelian study of the species problem: The im- 
portance of this line of research for the understanding of PORTES 
phical and biosociological questions is also evident. 
February 5th, 1922. 
LITERATURE CITED. 
1. DREJER, S. T. N. 1838. Flora excursoria Hafniensis. — Hafniae. 
2. HERIBERT-NILSSON, N. 1918. Experimentelle Studien über Variabilität, Spalt- 
ung, Artbildung und Evolution in der Gattung Salix. — Lunds Universitets 
Ärsskrift, N: F. Avd. 2, Bd 14, Nr. 28. 
3. — 1920. Zuwachsgeschwindigkeit der Pollenschläuche und gestörte Mendel- 
zahlen bei Oenothera Lamarckiana. — Hereditas I, 41—67. 
4. JOHANNSEN, W. 1913. Elemente der exakten Erblichkeitslehre. — 2. Aufl. 
Jena. 
5. KÔLREUTER, D. J. G. 1761. Vorläufige Nachricht von einigen das Geschlecht 
der Pflanzen betreffenden Versuchen und Beobachtungen. Leipzig. 
6. LinpMAN, C. A. M. 1918. Svensk fanerogamflora. Stockholm. 
ain Bev 
