As a function of site conditions, floristic composition and vegetation structure, DCGs represent a mosaic of environments, including subnival pioneer communities, glacier foreland early- to late-successional stages, morainal locations, and locally, even forest sites. An increasing body of evidence shows that, given a minimum of debris thickness and sufficient substrate stability, DCGs host surprisingly diverse plant assemblages, both floristically and structurally, despite being obviously cold and in parts also highly mobile habitats. Scientific interest in debris-covered glaciers (DCGs) significantly increased during the last two decades, primarily from an abiotic perspective, but also regarding their distinctive ecology. Vaigach) Ic - Iceland Fa -The Faroes BI -Northern British Isles SS -Scandes, southern part NF -Fennoscandia, northern part including the Kola Peninsula. The nine geographic regions analyzed for endemic vascular plant taxa are indicated: GW -Greenland, West and South (SE to Lindenowfjord) GE -Greenland, East (N of Lindenowfjord) Sb -Svalbard including Bear Island and Franz Josef Land NZ -Novaya Zemlya (excl. The ice-free coastal shelves south and northeast of the coalesced North European ice sheets, on the other hand, were directly connected to the periglacial continental tundras and may have served as important source areas for postglacial immigration. The ice-free coastal shelves along the margins of the Greenland and North American ice sheets are potential refugia relevant for the nunatak hypothesis of glacial survival. Red symbols represent ice-free areas for which strong geological evidence is available grey symbols represent areas suggested in recent literature but for which strong evidence is not yet available. Occurrences of extensive ice-free uplands, nunatak (ice-free mountain) areas, and ice-free dry shelves in the North Atlantic region at the time of the Late Weichselian maximum ice extent are indicated. Reconstruction of the Late Weichselian (25,000–10,000 years ago) maximum ice limits in the North Atlantic area compiled from various sources (Funder & Hansen, 1996 Landvik & al., 1998 Svendsen & al., 1999 Dyke & al., 2002 Mangerud & al., 2002). In other species, there are deep trans-oceanic phylogeographic splits suggesting survival in two or more refugia, but these refugia may have been located outside the ice sheets. Molecular data suggest that many plants and animals have migrated recently across the Atlantic, even if they lack mechanisms promoting long-distance dispersal. There is now strong geological evidence for some ice-free North Atlantic areas within the maximum limits of the Late Weichselian/Wisconsian ice sheets, but no fossils have been found to prove continuous �in situ� existence of life in these areas. Herein we review recent geological, molecular, taxonomic, and biogeographic data to re-examine this view. The alternative �tabula rasa� hypothesis of postglacial immigration was regarded to be of merely historical interest. Up to the 1960s, there was nearly complete consensus that disjunctions and endemism in the North Atlantic cannot be explained without �in situ� survival during the glaciations (the nunatak hypothesis).