Borovichev E.A. Botanical excursion on the Northern Soroya. Hammerfest, 2014.

Species o f screes Moving sloping screes are covered primarily by crustose lichens. Other forms o f lichens have difficulty surviving in these habitats. Screes offer an opportunity to observe soil formation and plant succession, after pioneer species o f lichens destroy the rock surface by physical and chemical activity (hyphae of the lichens go through the stone particles and lichen acids dissolve them). They produce a thin layer o f primary soil, in time their descendants carry on and make the soil layer thicker. Epilithic lichens are essential for the development of primary soil and first stages of plant cover. from the harsh environment Placopsis gelida is a lichen which consisted ofthree types oforganisms:fungus, green and blue-green algae (producing brown cephalodia in the center o fthe thallus) 97