There are a wide variety of plant species which fit the category of glacial relict. The ones given here are a small selection of the much larger group. • A tall
deciduous tree genus,
Liriodendron, was widespread across
temperate regions of the Northern Hemisphere until the onset of continental glaciations. The genus took refuge in southeast Asia and southeast North America, expanding to occupy today's temperate habitats. The east-west orientation of mountains in Europe is thought to be the geographic barrier that prevented the genus from migrating far enough southward to avoid extinction. • The
biogeography of various aquatic species deemed glacial relicts that are found in
Lake Sommen is likely related to a different geography during the early history of the lake. One theory claims that aquatic species were transferred from the
Baltic Ice Lake through a natural
lock system in connection with a temporary advance of the ice-front during the
Younger Dryas. On land, the unusual occurrence of
dwarf birch near
Sund is also judged to be a leftover from a cold geological past. • The
Franklin tree (
Franklinia alatamaha) was a glacial relict in the American Southeast and endemic to the
Altamaha River valley in Georgia before going
extinct in the wild in the early part of the 19th century. Like various other plants in this region of the United States, it grew in a lowland
glacial refuge. Due to changing temperatures in the
Holocene, it was unable to survive - it likely originally dispersed as seeds floating down the Altamaha River, but due to the nature of rivers, it was unable to make the reverse journey to cooler upland climes and survive rising temperatures. This species was the subject of a number of enthusiastic searches to locate potential wild populations in the 20th century, but it was never found in the wild after its original extinction and reintroduction efforts in the early 21st century failed. • Examples of other endemic plants in the Southeastern USA which were limited by the same environmental factors include the
Florida torreya, the
Florida yew, and the now-extinct
Critchfield spruce. ==See also==