STUDIES ON THE VEGETATION OF ICELAND 
.. 
—1 
TABLE 18. Biological Conditions in Mo, Flag, and Jadar 
at Björk (I) and Lækjamot (Il). Cf. the text. 
Number | Density | 
a 5 < ‘Clo KT G Th 
of species | of species | | | 
mo... | 39.7 148 | 289 | 523 | 188 | 0.1 
LT LASER SE BOV ODER rssh ARE SE ES ON ECTS | 20.9 
SETS EIER 42.0 13.8 | 22.3 | 536 | 241 | 0.2 
ost m nenne 42.5 159 | 247 | 580 | 141 | 3.3 
SEA MNO! a. ce vs 629.09 A dO 18.0 62) 10:7 9.4 
Myri vegetation......... | 30 | 112 | 12.5 39.9 | 45.9 21 
I | EN Eg NE 
b | A | ELA TEA 2 ARE BES | ER JE 
| | | 
| || | | 
Bi Meist mo.........: 39.3 | 60.7 | 19.3 | 9.6 | 10.4 | 32.6 | 10.8 | 16.8 | 0.5 
LT OT ANRT | 52.8 | 47.2 | 36.1 | 16.5 | 0.1 | 18.1 | 27.7 | 11 | .0.3 
LICE ENT | 35.6 | 64.4 | | 15.0 | 8.2 | 12.5 | 35.8 | 13.5 | 14.9 | 0.3 
| == all zu 
II. Moist mo.......... | 56.5 | 43.5 | 32.6 | 15.9 | 8.0 | 22.6 | 10.2 | 88| 2.0 
ea.) | 63.3 | 36.7 1415 BAR: aN 4 re 1.2: nes 
Myri vegetation.... | 50.0 | 50.0 | 22.6 | 25.1 | 23 | 246 | 165 | 87 
portion of Th, G, and H is no doubt directly dependent on the 
comparatively strong desiccation of the flag in the summer. 
On passing from the mo to the myri on gently sloping ground, 
in places where no flag vegetation has been developed, there will, 
as will be shown in more detail later on, occur a decrease of the 
Ch percentage and an increase of the H, Th, and G percentages at 
the level answering to the flag zone. Apart from the geophytes this 
is the same change as characterised the flag vegetation. Hence 
the flag vegetation must not be regarded as such an 
isolated phenomenon as its physiognomy and peculiar 
biology would seem to suggest at a first glance, it must 
be regarded as an extreme stage of development of those 
conditions of environment which are found and act in 
the stage of moisture with which the flag vegetation is 
associated. 
If we consider the species group spectrum, here, too, we shall 
find a peculiar difference between the flag vegetation and the sur- 
rounding types. The proportion of arctic plants is comparatively 
high in the flag, and this is due to a rise in the A3 and A 2 per- 
