THE PROBLEMS OF ANTARCTIC PLANT LIFE. 11 



of the Pourquoi Pas ? speaks l of the almost continuous carpets of Usnea at 

 Deception Island. 



Two other species, Rhizocarpon geogr.aphicum, D.C., and Letideafusco-atra,, Th. Fr., 



are less abundant, and owing to their more sombre colour and less striking appear- 

 ance do not, as a rule, lend any very characteristic feature to the landscape. The number 

 of Antarctic lichens so far known is 88, but the reports on several recent collections 

 have yet to be published. Future exploration will certainly add greatly to this number. 

 Eleven species were found by the Scotia at the South Orkneys, and with regard to these 

 Dr 0. V. Darbishire reports 2 that all except one were previously recorded from some 

 part of the Arctic regions, and that, taking into account all known collections, the pro- 

 portion of Arctic species is as high as 73 to 75 per cent. Of the Discovery collections 

 76 per cent, were also Arctic in distribution. The lichens of Gerlache Strait as collected 

 by the Belc/ica numbered 55, including a new species of Placodium (P. regale, Wainio), 

 which was also found by me at the South Orkneys and independently described as 

 P. fniticulosum, Darbish.: Wainio's name, however, has priority. Of these 55 species 

 38 '2 per cent, were known from Arctic regions, and as many as 527 per cent, were new. 

 All the 3 species recorded from Wilhelm Land are of wide distribution. Since these 

 statistics include in each case many cosmopolitan or very widely spread species, which 

 are common among lichens, it would be unwise to base on them arguments concerning 

 the origin of the Antarctic flora, 



The multicellular algae of Antarctic seas are quite abundant as regards individuals, 

 if perhaps the species are not very numerous. Fifteen species are recorded by Mr and 

 Mrs Gepp from my South Orkney collections, and Mr Holmes records 9 other species 

 in a small collection made by the expedition in the same place. Of the species deter- 

 mined by Mr and Mrs Gepp, 5 are new. I am confident that careful exploration of 

 the coasts of these islands at seasons when they are free from ice would reveal many 

 more species. As was only to be expected, the littoral region, i.e. the area between 

 high and low water, proved poor both in individuals and species ; calcareous species are 

 the most abundant in that region. The wearing and tearing action of the ice is not 

 compatible with much algal growth in these shallow waters, and this no doubt accounts 

 for the absence of the southern kelp (Macrocystis pyrifera) from the true Antarctic 

 regions. The majority of the algse occur at greater depths. The daily haul of the 

 dredge which we took in Scotia Bay scarcely ever failed to bring up specimens of algse, 

 The two red algse (Plocamium coccineum, Lyngb., and Acanthococcus spinuliger, Hook, 

 and Harv.) were extraordinarily abundant in 10 fathoms, and the brown alga (Desma- 

 restia Rossii, Hook, and Harv.) was frequent in shallower water. Calcareous algse 

 were obtained almost daily in 9 to 10 fathoms. In places these algse cover the rocks 

 in a few feet of water with so continuous an incrustation that at first sight one is 

 deceived into the belief that it is an ice formation. Probably the most interesting find 



1 Rapports pr&imina/ires sur les travaux executes dans I'antarctique, Academic des Sciences, Paris, 1910, p. 99. 



2 See this volume, pp. 24-29, and " The Botany of the South Orkneys : Lichens," O. V. Darbishire (loc. cit.). 



