The Botany of Iceland - 01.12.1914, Page 153

PHYSICAL GEOGRAPHY
337
are oí'len met with, but upon the knolls there are Elyna Bellardi
and Jnncus trifidus-, sometimes these are intermixed with mosses
and lichens. In some places Juncus balticus predominates, in others
Luzula or Agrostis, Aira cœspitosa, Trisetum subspicatum and otlier
grasses.
The dry uncultivated grassland without knolls (hardvelli, vall-
lendi) usually has for a substratum coarse sand, river-gravel, pebbles,
etc., with a thin covering of humus, and a low and rather open vege-
tation which chiefly consists of Gramineæ (Festuca, Aira, Poa and
Agrostis), but these are abundantly intermixed with Juncus balticus,
Lnzula multiflora and L. spicata and Elyna Bellardi; Festuca rubra is
sometimes a dominant species. Of dicotyledonous plants the fol-
lowing arecommon: Leontodon antumnalis, Thalictrum alpinum, Draba
uerna, Galium verum, Euphrasia officinalis, Viota tricolor, Gentiana
campestris, Achillea millefolinm, Rhinanthus minor, and others.
The home-field (tun) is the manured grassland round the farm-
buildings. It is usually enclosed and generally abounds in Iarge
knolls. In 1909 the area of the home-fields throughout the island
was estimated at 188 square kilometres. The hay (tada) from these
home-fields is kept chielly for winter-fodder for cows. The culti-
vation of the home-fields differs greatly, which again influences the
vegetation, other plant-associations occurring in patches in the grass-
covered area of the home-íield; these are especially dependent upon
the degree of moisture contained in the different parts of the field.
In really well-cultivated liome-fields throughout the country the vege-
tation is everywhere homogeneous. The Gramineæ are dominant,
especially Aira cœspitosa, Poa pratensis and Festuca rubra\ moreover
Festuca ovina, Poa trivialis, P. annua, Agrostis vulgaris, Alopecurus
geniculatus and Anthoxanthum odoratum are very common, and inter-
mixed abundantly with these occur Ranunculus acer, Taraxacum offici-
nale, Rumex acetosa and Polygonum viviparum. The home-fields are
often quite yellow with Ranunculi (R. acer and R. repens)-, in many
places Trifolium repens and Rhinanthus minor also occur abundantly.
In some places Viola tricolor is abundant in liome-íields, especiallv
in Eyjafjördur, and Geranium silvaticum in some places in Myrdalur,
and in other places ITa'a cracca, etc. In addition, many other plants
are found in patches, according to the dampness of the soil and
the care given to the cultivation of the home-fields; in dry and
sandy grassland there often occur an abundance of Galium verum,
G. silvestre, G. boreale, Achillea millefotium, Leontodon autumnalis,