THE PROBLEMS OF ANTARCTIC PLANT LIFE. 15 



have contributed to Coats Land and the coast eastward towards Enderby Land. The 

 floras of all these sub-antarctic islands from the Falklands eastward to Kerguelen have 

 been shown to be related to one another, and to have strong Fuegian affinities ; and 

 Dr Cockayne has pointed out the relationship between the flora of Kerguelen and that 

 of Macquarie Island. 



In a later part of this paper (pp. 17-20) is a fuller discussion of these islands and 

 their floras ; but this close relationship with Fuegia that they all exhibit, means that 

 emigration of a species from any of these islands to Antarctica amounts to emigration 

 from Fuegia by a somewhat circuitous route. No other lands are near enough to 

 Antarctica" to have affected its flora. 



In relation to the flora of South Georgia, Dr Skottsberg has discussed at some 

 length the probability of wind and bird carriage of various species : reference should 

 be made to that paper. 1 Taking into account our incomplete knowledge of the 

 Antarctic flora, the total number of species which occur in Antarctica may seem large 

 when all must have been brought by such chance agencies as wind and birds ; yet I 

 believe that the existing species in Antarctic regions represent a small proportion 

 of those that have reached there. The probability of seeds and spores reaching a 

 location suitable for growth is small, and even then only specially favoured species 

 could survive the adverse conditions of life with which they have to contend. The 

 high proportion of endemic species among the mosses in particular is, of course, the 

 outcome of this most specialised environment. 



One element of the Antarctic flora may appear to present a difficulty in the way 

 of the acceptance of this theory that is, the northern element. Dr Cardot has found 

 a large proportion of these forms among the mosses of both Antarctic and sub-antarctic 

 regions. But their presence can be satisfactorily explained, and that without recourse 

 to the now discredited theory of bipolarity. Dr Cardot suggests 2 that the spores and 

 soredia of these mosses and lichens may be transported on the feet and plumage of 

 those birds which we now know wander between high northern and high southern 

 latitudes. Wilson's petrel (Oceanites oceanicus), which breeds in the Arctic regions, 

 was found by us during the northern winter off Coats Land ; the northern tern 

 (Sterna macrura) was proved by the naturalists of the Scotia to wander almost from 

 pole to pole ; and other species of birds might be cited that range between Alaska and 

 Fuegia. While there may be some degree of probability in Dr Cardot's theory, I do 

 not feel it gives an adequate explanation of the facts, and I think that a more satis- 

 factory and simpler explanation is to be found in the idea that the species of mosses 

 and lichens in question are either cosmopolitan, but have not been discovered in low 

 latitudes, or that they are species which have spread from northern to southern regions 

 (or vice versa) by means of mountain ranges or bird and wind transport, but which 



1 "Die Gefasspflanzen Sudgeorgiens," Carl Skoltsberg, Wissen. Erg. Schwed. Siidpulur-Ej-ji., iv. 3. 



2 " Note sur la Flore de 1'Antarctide," Jules Cardot, Comptes rendus de VAssoc. Fran^aisepour Favancement des Sciences, 

 1907, pp. 452-460. 



