In southern Iceland you find large lava fields covered with continuous mats of moss, while lava fields in northern Iceland often have less moss but more lichens. Northern Iceland has a drier climate than southern Iceland. Montane Moss (Racomitrium lanuginosum) is often pronounced. In northern Iceland, for example, in the Myvatn district, a species of tree-shaped lichen, Sterocaulon vesuvianum, is common. Many lichens grow better in the dry climate of northern Iceland. Rushes, such as Spiked Wood-rush (Luzula spicata), Three-leaved Rush (Juncus trifidus) and Bellard's Kobresia (Kobresia myosuroides) and sedges such as Curly Sedge (Carex rupestris) are found interspersed within the mat of nonvascular mosses and lichens. Grasses, herbs and low-growing shrub also grow on the lava, while deep in lava crevices you find ferns.
Lava fields that are protected from grazing are eventually overgrown by woody plants Tea-leaved Willow (Salix phylicifolia) and Downy Birch (Betula pubescens). In north Iceland the smaller species of Dwarf Birch, Betula nana, is also quite common. Irregular rock-formations in the lava fields are often covered with nutritious guano suitable for the growth of colourful lichens such as orange coloured Sunburst Lichens (Xanthoria elegans) and the greenish-yellow Lecanora muralis.