THE GENOTYPICAL RESPONSE OF THE PLANT 237 
D. MELANDRIUM RUBRUM. 
No succulent coast form of this species seems to have been recor- 
ded. Such a form grows, however, on the sea cliffs of Kullen in 
N. W. Scania. It has been in culture for two years and does not 
yet show any decrease in thickness. Fig. 76 f represents a cross-section 
of a leaf of the ordinary type, cultivated since 1920, so common in 
the beech woods of Scania. Fig. 76e shows a cross-section from the 
cultivated, succulent Kullen type made in 1922. The thickness of the 
leaves of the cultivated type of the beech woods varies between 295u. 
and 350 «., while the leaves of the cultivated plants belonging to the 
type from Kullen vary between 575 «. and 615 «. The measurements 
refer to well-developed rosette leaves in autumn. 
Great variation is found within both types in regard to the shape 
and hairiness of the leaves, the shading of the red colour of the flower, 
etc., but the characteristics of the leaf thickness are peculiarly uniform 
in each of the two types. 
It should not be thought that succulence is characteristic of the 
coast type of Kullen only. Alpine varieties of this species, now 
brought under culture, seem to be still more fleshy. The material is 
too young to allow definite conclusions to be drawn, but a few plants 
belonging to this Alpine type, transplanted from Jämtland in 1918 and 
cultivated by Professor Nitsson-EHLE in the same field as the above- 
mentioned Lowland types, have been examined as to leaf succulence 
this autumn (1922). The leaf thickness was found to vary between 
645 u. and 735 4. Fig. 76d represents a cross-section of a rosette leaf 
from one of these plants. 
There are, no doubt, additional examples of thin-leaved inland 
plants represented by succulent types both along the coast and in the 
mountains. Preliminary work on Rumex acetosa L. seems to point in this 
direction. These coast and Alpine types of one and the same species 
represent an interesting illustration of the fact so well known among 
plant geographers that one and the same species may be found both 
along the coast and in the Alpine regions (ScHimpEr, 1908). It has 
yet to be shown, however, that these species really are represented by the 
same hereditary type in both localities. That this is not so in the 
case of the above-discussed plants seems certain. 
The results of the cultivation of succulent coast types discussed 
above leave little room for doubt as to the genotypical differences 
between these types and the corresponding inland types. That the 
