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

not flat in cross-section but mostly three-dimensional. Crustose lichens form crusts that are so tightly attached to the rocks, bark o f shrubs or soils that they can’t be removed without damaging the substratum. Basing on substrata lichens are growing upon, they are subdivided into epiphytes, which are living on other plants, epigcous lichens, which occur mainly on the soil and fine earth, and epilithic lichens, which grow on the rock surface. Crustose lichens even can grow immersed in rocks with only their fruiting bodies above the surface. It should be emphasized, r, ,. I , „ ,. , , , that these lichen substrata groups roliose lichens of genus reltigera mamly occur on soil, but can grow o r on rock, tree bark, and on mosses a growth forms do not lepiesent taxonomic groups and include rhizines. Cortex is «tissue» consisting o f fungal various different taxonomic filaments and an algal layer located inside the groups, thallus where the algae cells are enclosed in a hard but loose network o f the fungal filaments. The thallus may contain fruiting bodies: apothecia which are open fruiting bodies containing fungal spores: perithecia - the same as apothecia, but closed; ceplialodia - containing blue-green algae. The lichen thallus has organs o f vegetative reproduction - soredia, which represent clumps formed by algae cells and fungal filaments which can break away from the thallus and after being transported by wind or water, grow as a new thallus. Clusters o f soredia are named soralia. Isidia is the same organ as soredia, but covered by the cortex. All lichens may be separated into following major groups based on morphology of the thallus. Foiiose lichens are leaf-like, composed o f lobes and relatively loosely attached to the substrate, usually by rhizines. Their lobes have upper and lower sides and usually grow more-or- less parallel to the substrate. Umbilicate lichens are attached to the substrate only at a central point. Fruticose lichens are looking Xanthoria parietina is a widely distributedfoiiose lichen like tiny shrub, their branches are generally which grows on nutrient-rich substrata: on sea rocks and inland below birdperching areas 90