THE GENOTYPICAL RESPONSE OF THE PLANT 285 
It is much to the purpose to start with the description of H. umbella- 
tum from the northern part of this eastern coast strip of Scania and 
then to proceed southwards. List nos. 29 and 30 refer to series from 
Ahus, the former series collected in the epilittoral belt, which is here 
composed of an almost closed turf of vegetation, the latter series col- 
lected in the moss-carpeted floor of the planted pine woods some 
hundred metres from the beach. Table 22 gives the result of the cul- 
tivation of these series, which were started in 1919. The similarities 
as to the characters of leaf, leaf margin and inflorescence between these 
series and the dune form series from the west coast is at once seen. 
There is, however, one striking point of difference between the ma- 
4 
* 
me 
je 
wi 
Fig. 50. H. umbellatum. Cult. dune type from Ähus. 
terial from Ähus and the west coast dune forms. The large majority 
of the indivduals from Ähus show extreme prostrateness of their stems 
and keep the terminal part of the stems at an angle of about 45° with 
the vertical (see also fig. 50). The same extreme prostrateness may 
be found in the west coast dune series but the regularity of this feature 
is much greater in the former series than in the latter. There is another 
point of difference between the two series, which is not shown in the 
tables. The west coast dune forms show a marked shoot-regenerating 
power during autumn, while the eastern dune representative does not 
show any, or a very weak, power of regeneration. The distribution 
of this characteristic form is rather extensive.‘ It occurs frequently in 
the sand field area of north-eastern Scania and ceases to the west, 
where the sand fields cease, grading into the inland form of the 
