The Botany of Iceland - 01.12.1945, Side 69

The Botany of Iceland - 01.12.1945, Side 69
THE VEGETATION OF CENTRAL ICELAND 411 of a lowland character was found except on the banks of the brook flowing from the spring. However, these springs are not as hot as those on Landmannaafrjettur (c. 43°C. as against 72°C.). Moreover, the Laugar at Snæfell are unsheltered, and the snow-covering does not exceed the norrnal. These two examples show that a considerable heat of the soil is required if it is to exert any actual influence on the vegeta- tion of the surrounding area. b. TheBrekkur Vegetation (the vegetation of the hillsides). The formation to be dealt with here is very similar to that of the grass field. It is found on dry ground, and its surface is without knolls; the vegetation is closed, and Gramineae or gramineous plants dominate. Nevertheless I have chosen to record it as a separate formation on ac- count of the nature of the surface; the surface always slopes, at times showing a very considerable inclination. It is almost exclusively found on the lower parts of the mountain sides, particularly where these have a southward or eastward exposure. Higher up the phanerogamous vege- tation is more scattered, and the brekkur vegetation passes into the Grimmia heath. The difference between the phanerogamous vegetation of these two formations is inconsiderable, but in the Grimmia heath the phanerogams present are much reduced in number by the Grimmia, so that the “Feldschicht”, which is entirely closed in the brekkur vegeta- tion, is very open here. The distinction between these formations is mostly fairly sharp. The brekkur vegetation has not, as a rule, a partic- ularly thick or long-lasting snow-covering, so in that respect it differs greatly from the snow-patch formation, which is often found in grooves and depressions in the brekkur vegetation. Of all the formations of the meadow series, the brekkur formation as a rule exhibits the thinnest snow-covering. The brekkur formation is rich in species, and the density of the species is comparatively high considering the height above the sea. How- ever, there is a considerable difference in these features according to the situation, altitude, and exposure of the individual localities, which will be explained in more detail under the description of the individual associations. The A percentage is generally fairly high, relatively higher than in the mýri and the heath series, but is still subject to considerable fluctuations. H is the dominant life-form, though Gh is more prominent in some few associations. Within the meadow series the brekkur vegeta- tion shows the highest A and Ch percentages. 28*
Side 1
Side 2
Side 3
Side 4
Side 5
Side 6
Side 7
Side 8
Side 9
Side 10
Side 11
Side 12
Side 13
Side 14
Side 15
Side 16
Side 17
Side 18
Side 19
Side 20
Side 21
Side 22
Side 23
Side 24
Side 25
Side 26
Side 27
Side 28
Side 29
Side 30
Side 31
Side 32
Side 33
Side 34
Side 35
Side 36
Side 37
Side 38
Side 39
Side 40
Side 41
Side 42
Side 43
Side 44
Side 45
Side 46
Side 47
Side 48
Side 49
Side 50
Side 51
Side 52
Side 53
Side 54
Side 55
Side 56
Side 57
Side 58
Side 59
Side 60
Side 61
Side 62
Side 63
Side 64
Side 65
Side 66
Side 67
Side 68
Side 69
Side 70
Side 71
Side 72
Side 73
Side 74
Side 75
Side 76
Side 77
Side 78
Side 79
Side 80
Side 81
Side 82
Side 83
Side 84
Side 85
Side 86
Side 87
Side 88
Side 89
Side 90
Side 91
Side 92
Side 93
Side 94
Side 95
Side 96
Side 97
Side 98
Side 99
Side 100
Side 101
Side 102
Side 103
Side 104
Side 105
Side 106
Side 107
Side 108
Side 109
Side 110
Side 111
Side 112
Side 113
Side 114
Side 115
Side 116
Side 117
Side 118
Side 119
Side 120
Side 121
Side 122
Side 123
Side 124
Side 125
Side 126
Side 127
Side 128
Side 129
Side 130
Side 131
Side 132
Side 133
Side 134
Side 135
Side 136
Side 137
Side 138
Side 139
Side 140
Side 141
Side 142
Side 143
Side 144
Side 145
Side 146
Side 147
Side 148
Side 149
Side 150
Side 151
Side 152
Side 153
Side 154
Side 155
Side 156
Side 157
Side 158
Side 159
Side 160
Side 161
Side 162
Side 163
Side 164
Side 165
Side 166
Side 167
Side 168
Side 169
Side 170
Side 171
Side 172
Side 173
Side 174
Side 175
Side 176
Side 177
Side 178
Side 179
Side 180
Side 181
Side 182
Side 183
Side 184
Side 185
Side 186
Side 187
Side 188
Side 189
Side 190
Side 191
Side 192
Side 193
Side 194
Side 195
Side 196
Side 197
Side 198
Side 199
Side 200
Side 201
Side 202
Side 203
Side 204
Side 205
Side 206
Side 207
Side 208

x

The Botany of Iceland

Direkte link

Hvis du vil linke til denne avis/magasin, skal du bruge disse links:

Link til denne avis/magasin: The Botany of Iceland
https://timarit.is/publication/1834

Link til dette eksemplar:

Link til denne side:

Link til denne artikel:

Venligst ikke link direkte til billeder eller PDfs på Timarit.is, da sådanne webadresser kan ændres uden advarsel. Brug venligst de angivne webadresser for at linke til sitet.