330 THORODDSEN 



situation is suited to plant-life with southern exposure, an adequate 

 supply of water, shelter from sharp winds, and intense sunlight 

 during spring a "herb-slope" (Urteli 1 ) or "herb-flat" (Urtemark) is 

 formed which on the one hand passes gradually into a rocky-flat 

 formation, and on the other into a birch coppice; it chiefly contains 

 the plants of these two formations, but the growth is dense and 

 luxuriant, so that the ground often appears to be entirely covered 

 by the closely-placed plants. Dicotyledonous flowering plants are 

 the most important, grasses are absent or of subordinate importance. 

 The soil consists of clay or gravel mixed with humus, upon which 

 mosses sometimes occur. Such herb-slopes are found in patches 

 on mountain-sides, on basalt-terraces or on the inclines below rocks, 

 in large ravines and in sheltered, sunny hollows; they often form 

 beautiful carpets, in which the various species usually occur inter- 

 mixed with each other. As a rule, the dominant species are Gera- 

 nium silvaticum , Spircea ulmaria, Archangelica officinalis, Angelica 

 silvestris, Geum rivale, Bartschia alpina, Alchimilla viilgaris, Brunella 

 uulgaris, Rnbus saxatilis, Vicia cracca, Myosotis arvensis, Leontodon 

 autiimnalis, several species of Hieracium, Rnmex acetosa, Ranunculus 

 acer, Poa, Agrostis and Aira; intermixed with these occur several 

 other species, but less frequently. In some parts of the island other 

 characteristic species are frequently noted in "herb-slopes," for in- 

 stance in East Iceland, Campanula rotundifolia and Saxifraga aizoi- 

 des, and in some places in South Iceland Valeriana officinalis and 

 Lychnis flos cnculi. 



Sand-covered tracts (sandar). As already mentioned, sand} 7 

 tracts occupy vast areas several thousand kilometres surface 

 in Iceland, both in the lowlands and on the plateau. The physical 

 conditions of these "sandar" differ somewhat, therefore their vege- 

 tation, although usually homogeneous and poor in species, may now 

 and then vary somewhat in details. The vast sandy wastes below 

 the glacier-bearing mountains (Jokulls) of South Iceland are mainly 

 formed of glacio-fluvial gravel and sand, but also partly of volcanic 

 ashes and scoriae, while there are wide stretches upon which both 

 the line and the coarse gravel is mixed with clay. Sometimes exten- 

 sive stretches are occupied by alternating clayey flats and pebble- 

 covered river-beds; there are also tracts strewn with ice-striated 

 boulders, and extensive areas, especially on the plateau, covered 



Urteli ^herb-slope) and Gnesli (grass-slope; see p. 335) denote plant-covered 

 slopes where dicotyledonous flowering plants and grasses are dominant respectively. 



