DISTRIBUTION 347 



as Cladontae, Lecanorae or Lecideae. On the soil, Lecanorae cover the largest 

 areas. 



Wainio determined a large number of lichens with many new species, 

 but the region is colder than that of Lappland, and trees with tree-lichens 

 are absent, with the exception of those given above. In Arctic Siberia, 

 Elenkin' discovered a new lichen Placodium subfruticulosum which scarcely 

 differs from Darbishire's^ Antarctic species PI. fruticulosum (or P. regale); 

 both are distinguished by the fruticose growth of the thallus, for which reason 

 Hue^ placed them in a new genus, Polycauliona. 



The Antarctic Zone and the neighbouring lands are less hospitable to 

 plant Hfe than the northern regions, and there is practically no accumulation 

 of detritus. Collections have been made by explorers, and several lists have 

 been published which include a marvellous number of species common to 

 both Poles, if the subantarctic lands are included in the survey. An analytic 

 study of the various lists has been published by Darbishire^. He recognizes 

 106 true Antarctic lichens half of which are Arctic as well. The greater 

 number are crustaceous and are plants common also to other lands though 

 a certain number are endemic. The most abundant genera in species as 

 well as individuals are Lecidea and Lecanora. Several bright yellow species 

 oi Placodium — PI. elegans, PI. murorum, etc., are there as at the North Pole. 

 Among the larger forms, Panneliae, Cetrariae, and Cladoniae are fairly 

 numerous; Usneae and Ramalmae rather uncommon, while members of the 

 Stictaceae are much more abundant than in the North. The common species 

 Oil Peltigera also oCcur in Antarctica, though P. aphthosa and P. venosa are 

 wanting; both of these latter are boreal species. Darbishire adds that lichens 

 have so great a capacity to withstand cold, that they are only checked by 

 the snow covering, and were bare rocks to be found at the South Pole, he 

 is sure lichens would take possession of them. The most southerly point 

 at which any plant has been found is 78° South latitude and 162° East 

 longitude, in which locality the lichen Lecanora stibfusca was collected by 

 members of Scott's Antarctic expedition (1901-1904) at a height of 5000 ft. 



A somewhat different view of the Antarctic lichen flora is indicated by 

 Hue' in his account of the plants brought back by the second French 

 Antarctic Expedition. The collection was an extremely favourable and 

 important one : great blocks of stone with their communities of lichens were 

 secured, and these blocks were entirely covered, the crustaceous species, 

 especially, spreading over every inch of space. 



Hue determined 126 species, but as 15 of these came from the Magellan 

 regions only 1 1 1 were truly Antarctic. Of these 90 are new species, 29 of 

 them belonging to the genus Buellia. Hue considers, therefore, that in 

 Antarctica there is a flora that, with the exception of cosmopolitan species, 



' Elenkin 1906. ^ Darbishire 1905. ' Hue 1915. ■■ Darbishire 1912. 



