214 GOTE TURESSON 
distances of 50 X 60 cm. Each plant has then space enough to in- 
crease in size, and the cultivation with tools between the plants be- 
comes easy. The cultures are kept free from weeds and are dug twice 
a year, in spring and in autumn. Among the species cultivated, only 
Leontodon autumnalis has been found to thrive less satisfactorily. The 
individuals of this species sometimes suffer badly from the attacks of 
cutworms (Agrotis spp.?) on the roots. A certain type of Hieracium 
umbellatum, viz. the broad-leaved sea-cliff type, is particularly da- 
maged and greedily eaten by rabbits, which has necessitated the fen- 
cing of the field. 
A few words should be said as to the kind of species used and 
as to the mode of collecting. It is clear from the nature of the study 
that only such species have been investigated as are very common and 
occur in different habitats. Such species are, for instance, Lysimachia 
vulgaris, Centaurea jacea, Solanum Dulcamara, Matricaria inodora, etc. 
It is further to be expected that if changes in the genotypical composi- 
tion of a species result in response to climatic or edaphic factors these 
changes would be most clearly brought out and most easily demonstrated 
in species which have an extended and uninterrupted distribution running 
through areas of different climatic and edaphic character. The coast line 
of southern Sweden, to which region most of the species dealt with in the 
following are to be referred, is well suited for investigations of this kind. 
There are marked climatic differences between the east coast and west 
coast, the latter being more maritime and exposed to the action of strong 
winds and atmospheric sodium chloride (cf. Froprn, 1912), and the 
physiographical features of the coast lines vary much, cliffs, dunes 
and salt marshes alternating. There are plant species which occur 
throughout this varied stretch of land, and some of these, viz. species 
of the genus Atriplex, Armeria vulgaris, Hieracium umbellatum, have 
been found to furnish important data and have therefore been trans- 
planted and cultivated on a large scale. 
In the collecting, the individuals of a species from a certain ha- 
bitat are carefully dug up, care being taken that no selection is made; 
they are then numbered and packed in sacks and posted. They are 
immediately planted in the experimentat field on arriving. In planting 
as much soil as possible is removed from the roots. When just planted 
they are watered once or twice and then left. When treated in this 
way, only very few of the plants are spoiled and die. 
In regard to the notes and measurements of the different cultures 
discussed in the following it should be said that the values given in 
