*Two or three Lichens, species of Cladonia, and a Moss, Rhacomitrium lanuginosum.
Those marked with an asterisk appear to be invariably present, the others are not so constant, but some are usually found.
Shortly after leaving Hveravellir the watershed of the island was crossed, and a marked difference in the flora was noticed in the valley, Thjofadal, on the southern side of the ridge, owing no doubt to the much greater rainfall which occurs on this, the south-western, side of the island.
Among plants noticed in this region, which had not been met with before, were:—
Draba alpina.
Cardamine bellidifolia, and
Ranunculus pygmæus (which grew upright in the valley, but was prostrate and creeping on the surrounding hillsides).
Fungoid diseases were very prevalent in the valley, and Saxifraga cæspilosa, which was extremely dwarfed on the high ridges, was in many places badly attacked by a rust fungus.
Saxifraga cernua was also affected by the conditions in this region, for in other localities north of the watershed all the plants were found with the usual terminal flower, but here no terminal flower was developed, and the upright stems bore leaves and bulbils only.
Epilobium latifolium occurred among the stones in the glacier streams, and a very decumbent form of Epilobium alpinum was common on the hillsides.
The hills all round were formed of loose morainic matter, the slopes consisting of fine sandy earth with pebbles, and the vegetation is distributed on the hillsides in the form of banks and terraces, thus giving the hills a peculiar appearance with very gentle steps. In some cases the vegetation has spread and grown over the edges of the terraces, and by further growth hummocks have been formed.