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Problerns of Bipolar Plant Distribution 221Fig. 6. Distribution of the genus Empetrum L. Reprinted from GooD 1926.ciurn, Seligeria and Eucladiurn (IRMSCHER 1929, p. 253-254 and fig. 36). Amongthe phanerogams at least Angelica ()>an ill-defined genus)>, according to CHEESEMAN1925, p. 682) may be referred to the same type.A wide boreal distribution combined with one very isolated austral outlierin southernmost South America is found in some genera of phanerogams, e. g.Litarella (SKOTTSBERG 1911), Ernpetrurn (also in Tristan da Cunha, fig. 6), Ohrysospleniurn(cf. DrELS 1937, p. 41) and Prirnula (mapped by PAx and KNUTH 1905,Pl. I, southern limit in the Old World on tropical mountains in Africa and Java).A similar distribution is found in the moss genus Oncophorus (IRMSCHER 1929,p. 251, fig. 35 ).A larger and less isolated South American outlier, stretching along the greaterpart of the Andes, is found in Saxifraga (fig. 7). In other genera, e. g. Alnus, wefind the Andearr distribution area connected with the main boreal one by a seriesof occurrences along the mountains of Central America and Mexico.Two main austral populations, one in southernmost South America and onein Australia and N e w Zealand, bot h of t hem widely separated from the borealpopulation of the same natural group of genera, are found in the genus pair Fagus­N othofagus (fig. 8). In this case the boreal population is now split up in to threewidely separated main parts, with fossil evidences of a more continuous earlierdistribution. But in the Oarex-section Atratae (mapped by HEILBORN 1924, fig.17, reprinted by IRMSCHER 1 929, fig. 3) the boreal distribution area is still morecontinuous. And in the greenish section (sect. Ohloronephrorna DR.) of the lichengenus N ephrorna, t here is on e circumpolar species in the N orth, on e species inNew Zealand, and one species in southernmost South America, which is intermediatebetween the New Zealand species and the boreal one (Du RIETZ 1926 b, p. 303; 1929,p. 633).