THE GENOTYPICAL RESPONSE OF THE PLANT PA | 
forms from the hereditary ones without cultivating the plants must be 
very great, or rather insurmountable. 
2. MATERIAL AND CULTURES OF LOWLAND DWARF FORMS. 
In our country dwarf forms are especially met with in Alpine ha- 
bitats, in the so called Alvar vegetation and in the salt meadows along 
the coast. Representatives of the two former groups have been culti- 
vated for too short a time to be considered here, and therefore only 
salt meadow dwarfs, already in culture for some years, will be discussed. 
The plants to be discussed at any length are Aster tripolium L., Succisa 
pratensis Moench. and Centaurea jacea L. 
A. ASTER TRIPOLIUM. 
A dwarf form of this plant is known to systematists under the 
name A. tripolium var. diffusus DC. It is a much branched plant, not 
more than 5 cm. high, and occurs in somewhat drier spots of the 
salt meadow than the ordinary, tall growing tripolium. A series of 
the form (in flower) was collected at Vellinge, south of Malmo, and 
transplanted in the autumn of 1919 together with a few rosettes of 
the ordinary form.’ The latter attained a height of between 45—70 cm. 
in 1920, then flowered, and died in the autumn. The dwarf, although 
flowering in 1919, lasted through the autumn and winter and flowered 
again 1920. The height of the 1919 plants varied between 3—5 cm. 
The plants grew taller in 1920, and the height now varied between 
10—16 cm. They were found to fruit fréely. Fruits were collected 
from one of the individuals; they were sown in the autumn, and the 
seedlings were forced in the green-house and transplanted into the 
open in May the following year. They all flowered in the autumn. 
Fig. 3 illustrates some of the resulting types in the series raised. The 
height of the plants in the series varies between 8—18 cm. There is 
great variation between the different individuals, especially in bran- 
ching. The plant to the left in the fig. has a wholly prostrate main 
axis, the plant in the middle has a number of ascending, equivalent 
branches, while the plant to the right has an erect main axis and 
smaller, ascending side branches. The same characteristics of the 
different plants both as to height and branching are seen this year 
(1922). The same is true of the original dwarfs transplanted in 1919, 
which do not show any tendency to change the habitus attained in the 
culture 1920. 
