DERIVATION OF THE FLORA AND FAUNA 



425 



Table VIII. 



l)istributio}i of angiosperms in Southeastern Polynesia. 



Marquesas 

 Tuamotu 

 Austral . 

 Rapa . . 

 Mangareva 

 Pitcairn . 

 Henderson 

 Total . . 



Number of 

 species 



151 

 44 



80 

 89 

 28 

 26 

 21 

 282 



Number of 

 endemics 



79 



3 



12 



44 

 3 

 2 



3 



156 



% 

 endemics 



52 



Woody species 



Number 



100 

 23 

 53 

 62 



17 

 19 

 15 



182 



% 

 66.2 



52.3 

 66.7 

 69.6 

 60.9 

 73- 1 

 71-4 

 645 



Brown (jj) regards southeastern Pol\-iiesia. with the Tuamotus in the centre, 

 as an old, submerged region: 



Affinities point to the Tuamotuan region as one of the ancient mid-oceanic centers 

 of origin for a large part of the dicotyledonous flora of southeastern Polynesia (HI. 6); 



and, speaking of the distribution of Fitcltia, he writes il.c. 364): 



The grouping and affinity of these allied species strongly suggest the Tuamotuan 

 region as the center of origin at a rather remote period, possibly at the dawn of the 

 Tertiary or somewhat earlier, when it may be assumed that high (pre-Tuamotuan) islands 

 existed in place of the low (Tuamotuan) atolls of the present. 



Within the Marquesas archipelago the sea is shallow: 



Apparently, an emergence of 100 meters would cause land to ap)pear in six places; 

 an additional emergence of 300 meters would unite or bring into close contact all 

 land areas of the archipelago. . . . Botanical evidences, outlined in an earlier paper,-*^ 

 indicate that the islands were at one time 1000 to 2000 meters higher than at pre- 



sent 



(I.e. I. 



The floristic affinities of this region is with Malaysia-AIelanesia-Australia; 

 there is no neotropical element in spite of the prevailing direction of winds and 

 currents. Brown, who could be expected also to look toward America, remarks: 



The Cichorieae, to which Fitchia belongs, are best represented in Europe and 

 America, pointing to a more remote American center of origin for the pre-Tuamotuan 

 ancestral stock. 



This brings up the Z^rW;'<?j'r;7J"-77/^w;/^j"r;7J" problem. The four dendroseroid 

 genera form a very natural group, Thamnoseris of Desventuradas Islands stands 

 apart, and so does Fitchia. If they are, at least distantly, related, and isolated 

 from all other Cichoriaceous genera, then the possibility of an Antarcto-tertiary 

 ancestry should be considered. I have, however, referred the Dendroseris assem- 

 blage to an ancient neotropical element, absent from the present continental flora, 



^ Proceed. 2d Pan-Pacif. Sci. Congr., \'ol. 2, 1923. 



