The Caucasus Mountains between the Black and Caspian Sea have several climatic zones and are rich in plant species, about a quarter of which are endemic. At a crossroads between continents, these mountains were a refuge during the ice ages for all the plant genera that were chased out of Europe by the intense cold. An example is the Caucasian zelkova or Caucasian elm, which can be found in Group 32. The lowlands of the Caucasus are filled with Caucasian alder, Black alder, and Caucasian wingnut. In the hilly areas of the range we encounter oak forests with various species that are not (yet) represented in Group 32. The understory of these forests is often quite distinct from the understories that we find in western European forests, with evergreen Boxwood species and rhododendron growing wild. Western and Central European species (e.g. European hornbeam, Serviceberry, Whitebeam) can coexist with oriental, Asian species (e.g. Eastern hornbeam, Tatar maple). The largest area of the group is occupied by a beautiful stand of Nordmann firs and Caucasian spruces, species that dominate the higher zones of the Caucasus. The Caucasian spruce is distinguished from other spruce species by its very short needles.