426 



C. SKOTTSBERG 



and Thamnoseris finds no better place, but to derive I-'iicJiia from an American 

 source seems little inviting. Another solution is, perhaps, in sight. Professor GUN- 

 N.\R ErdtmaN kindly told me that, to judge by the pollen morphology, Fitchia 

 may have to be removed from the Cichormm subfamily where J. D. HoOKER 

 placed it next to Dendroseris and where it has remained. 



There is in the Pacific Ocean no island of the size, geology and altitude of 

 Easter Island with such an extremely poor flora and with a subtropical climate 

 favourable for plant growth, but nor is there an island as isolated as this, and 

 the conclusion will be that poverty is a result of isolation — even if man is re- 

 sponsible for the disappearance of part of the flora, it cannot have been rich; 

 the Marquesas Is., which have been inhabited longer, I believe, and formerly 

 had a large native population, still preserve a fairly rich and varied angiospermic 

 flora, iialf of which is endemic. The distances are too great to be overcome 

 except on very rare occasions. The nearest land is to the west, the small most 

 easterly islets of the Mangareva (Gambler) group, but winds (S.E. trade-wind) and 

 currents are unfavourable for transport from \\'., and Plaster Island ai)pears to lie 

 away from the cyclonic tracks. Beach drift is responsible for the arrival of several 

 species, Ipomaea, Caesalphiia, Chowpodiwin, Teiragonia, Erytln^aea, Apium, Samo- 

 lus, Lycium and perhaps some grasses and species of Cyperus, altogether about 

 ^/g of the angiosperms. Storms bring light diaspores. but it is noteworthy that 

 Compositae are absent. I can find no special adaptations for bird carriage, but the 

 possibility of rare cases of epizoic transport cannot be excluded. However that 

 may be, Easter is a good example of an island peopled by "waifs and strays". 



Affinities are, as we have seen, with Malaysia-Australia or pantropical, whereas 

 the well-marked east Polynesian flora has contributed nothing, not even its leading 

 family Rubiaceae, rich in drupe-fruited forms. Sopliora torouiiro is allied to S. ''tetra- 

 pterd" of Raivavae and Rapa; I cannot tell if this is the true /^/r^a'/Z^r^, a native 

 of New Zealand, but I do not think it is, and as Brown's description (III. 120) 

 shows, it differs much from toromiro, which comes very close to 5. masaftierana. 

 Neither is of American ancestry: sect. Edwardsia is austral-circumpolar and gene- 

 rally regarded to be of Antarctic origin or, at least, history. 



\\ ith the exception of Lyciimi carolinianum var. scDidincoise. supposed to 

 belong to the beach drift, there is, if FitcJiia is definitely excluded, no American 

 element in the flora of southeastern Polynesia, nor is it expected there. It is, as 

 we have seen, found in Easter Island. Of the 3 endemic grasses, Stipa was ten- 

 tatively brought to the palaeotropical element, Axonopus to the neotropical. DaJt- 

 thonia is an austral-circumpolar, tricentric genus. Three American, not endemic 

 species, Cyperus eragrostis, Scirpus riparius and PolygonuDi aci/iiii>icit!i»i. remain 

 to be accounted for. 



If Piaster Island once had a richer flora is an open question. According to 

 newspaper reports a palynological survey of the swamp in the crater of Rano 

 Kao was planned for Heverdahl's recent survey. The thickne.ss of the loose, 

 water-soaked Campy lopiis peat was not measured by me; it is a somewhat dan- 

 gerous quagmire which cannot be bored with the usual methods, but samples may 



