Floristic and phytogeographic studies of the hepatic flora of the Aleutian Islands, Alaska

The hepatic flora of the Aleutian Islands, Alaska was compiled from over 4000 collections including historical collections in The University of Tennessee Herbarium and more recent, personal collections made during 1988 and 1990. Literature reports were also incorporated. A total of 135 species in 52 genera and 29 families are treated. Ten species are excluded. Taxonomic discussions include differentiation from related taxa and descriptions of deviant or noteworthy morphological forms (including the presence of reproductive material). Ecological and phytogeographical information accompany taxonomic discussions. Two species, putatively new to science, are described in detail and one species, Chiloscyphus gemmiparous Evans, is shown to have questionable generic placement. Thirty-nine species, including 14 new to Alaska and 9 new to North America, are added to the Aleutian flora. Aleutian distribution maps are provided for all species and world distribution maps for 18 species. An analysis of the worldwide distributions reveals the following percentages of species in 5 categories: 2.2% Cosmopolitan, 79.3% Circumboreal, 11.9% North Pacific Arc, 5.2% Western North American, and 1.5% Endemic. The large Circumboreal category is further divided into Widespread Circumboreal Species (53.3%) and Imperfectly Circumboreal Species (25.9%). The majority of the flora is derived from Circumboreal elements. Most of the Asiatic species are found on both sides of the Pacific (North Pacific element). It is concluded that the majority, if not all, of the hepatic flora postdates the last glacial maximum.