The Botany of Iceland - 01.12.1930, Side 188

178
H. M0LHOLM HANSEN’
Table 38.
Species-group spectra and biological spectra of the difFerent types of
Vegetation on Iceland, based upon statisticai investigations.
Numbcr of Localities examined Points-sum , Number of species Density of : species i A E .4 3 A 2 A 1 E4 E3 E 2 E 1 Ch H G HH 1 Th
Mosathembur íi 2568 9 2.3 83 17 70 13 1 14 1 4 » 27 40 33 » >
Melar i(> 10658 24 6.8 72 28 48 18 6 24 4 0.5 0.1 47 41 11 » 2
Mo 34 43908 33 13.3 53 47 30 15 9 27 10 9 0.5 31 52 16 » 0.5
Jaðar 8 10140 39 13.2 47 53 23 14 10 31 12 10 0.1 18 ! 53 28 1 1
Formýri 18 15240 26 9.4 49 51 22 18 9 38 12 1 > 24 21 49 5 0.2
Hallamýri 5 4180 25 8.3 44 56 17 22 5 25 21 11 » 8 28 58 6 1
Flói 9 1740 4 1.9 28 72 5 3 20 37 36 » » 2 13 76 10 >
Geiri 15 15374 27 11.0 37 1 63 23 10 4 24 26 13 1.1 34 50 16 » 0.1
Forest undergrowth 6 5592 33 8.6 28 72 14 10 4 22 37 11 3 12 72 16; » »
Subularia flag 2 404 5 2.0 14 86 14 » » 21 65 » > >H 1 18 ' » 71
Flag 5 4852 25 9 9 58 42 38 19 » 15 25 1.4 0.1 13 60 12 » 15
Valllendi 6 4092 18 6.9 25 75 16 0 3 9 20 18 36 2 13 67 20 > 1
5. The low temperature in winter being the factor which has
the greatest bearing on the vegetation, a natural system of the Ice-
landic types of vegetation, i. e. a system in which the factors are
given in the order of their degree of importance for the vegetation,
must give as the first principle of division the conditions of snow-
covering, as the next, the conditions of moisture, and so forth.
Hence, the types of vegetation investigated in this treatise must
be ranged in the following order.
I. Vegetation bare of snow.
1. Soil covered with moss
2. Soil covered with gravel •
II. Vegetation with normal snow-covering.
1. Soil dry
2. Soil moderately moist
a. Soil covered with vegetation, level
b. Soil covered with vegetation, knolly
c. Soil bare, with smallknolls
Mosathembur (moss
heath, Grimmia heatli)
Melar (fell field)
Mo
Valllendi
Jaðar (grass mo)
Flag (clayey flats)