XIII 
THE INFLUENCE OF ENVIRONMENT ON THE 
FORMS OF PLANTS 
By Geora Kuss, Pa.D. 
Professor of Botany im the University of Heidelberg. 
TuE dependence of plants on their environment became the object 
of scientific research when the phenomena of life were first investi- 
gated and physiology took its place as a special branch of science. 
This occurred in the course of the eighteenth century as the result 
of the pioneer work of Hales, Duhamel, Ingenhousz, Senebier and 
others. In the nineteenth century, particularly in the second half, 
physiology experienced an unprecedented development in that it 
began to concern itself with the experimental study of nutrition 
and growth, and with the phenomena associated with stimulus and 
movement; on the other hand, physiology neglected phenomena 
connected with the production of form, a department of knowledge 
which was the province of morphology, a purely descriptive science. 
It was in the middle of the last century that the growth of com- 
parative morphology and the study of phases of development reached 
their highest point. 
The forms of plants appeared to be the expression of their in- 
scrutable inner nature; the stages passed through in the development 
of the individual were regarded as the outcome of purely internal 
and hidden laws. The feasibility of experimental inquiry seemed 
therefore remote. Meanwhile, the recognition of the great im- 
portance of such a causal morphology emerged from the researches 
of the physiologists of that time, more especially from those of 
Hofmeister’, and afterwards from the work of Sachs*% Hofmeister, 
in speaking of this line of inquiry, described it as “the most pressing 
and immediate aim of the investigator to discover to what extent 
external forces acting on the organism are of importance in deter- 
mining its form.” This advance was the outcome of the influence of 
1 Hofmeister, Allgemeine Morphologie, Leipzig, 1868, p. 579. 
2 Sachs, Stoff und Form der Pflanzenorgane, Vol. 1. 1880; Vol. 11. 1882. Gesammelte 
Abhandlungen wber Pflanzen-Physiologie, u. Leipzig, 1893. 
