238 GOTE TURESSON 
presence of sodium chloride, in the amount found in the coast habitats, 
should in certain cases modify these coast types towards a degree of 
succulence not attained in the cultivated series (as we have found in 
the case of Solanum Dulcamara and Leontodon autumnalis) is not 
surprising when it is known that a great number of non-halophytic 
plants are also thus modified. There is — even in those series which 
have been found to be less succulent in the cultures than in their natu- 
ral habitats a distinct difference as to the thickness of the leaf 
between the cultivated coast types and the cultivated inland types from 
the Lowland. When the latter have been found to be thin-leaved, 
while the former, cultivated in the same bed under the same condi- 
tions, are found to be succulent, genotypical differences between both 
types as to leaf thickness must, no doubt, exist. This is made all the 
more plausible when the F,-segregation from the cross between the 
two Matricaria types, as well as the behaviour of the cultivated shade 
form of the Väderö Solanum, are remembered. The existence of 
succulent Alpine forms of some of these species also speaks in favour 
of the assumption that succulence by no means stands in any direct 
proportion to the quantity of mineral. salts present in the diffe- 
rent soils. 
This does not lessen the importance of the fact of the modificatory 
action of salt upon the plant; it must be emphasised, however, that 
the results of the cultivations do not support the idea that the halo- 
phytic forms of thin-leaved inland species, found habitually along the 
coast, are modifications called forth in direct response to the saline 
soil. The classification of these forms into a group of »facultativé» 
halophytes (Warning, 1906) must therefore be refrained from. They 
are, on the contrary, to be considered as obligatory as most of the 
well-known species confined in nature to saline situations. 
4, MATERIAL AND CULTURES OF DIFFERENT SPECIES 
OF HALOPHYTES. 
The cultural experiments with species of halophytes have been 
largely confined to the genus Atriplex, and the discussion pertaining 
to this topic will therefore be limited to species belonging to that 
genus. Atriplex patulum L., although not a regular halophyte, has. 
also been included in the discussion. 
No other genus would seem so suitable for investigations of this 
kind as Atriplex. ‘They are annuals, and several species of the genus. 
have long been known to be exceptionally polymorphic. ~ Various 
