XXX RHIZOPHORA 449 



both as regards the flowers approach the Asiatic Rhizophora 

 (R. tnucronata), the Fijian Selala resembles the Asiatic tree also in 

 its foliage, whilst the " Mangle grande '' or the Ecuadorian Selala 

 more resembles the typical American tree (R. mangle) in its leaves 

 and also in its seedlings. Here in the Ecuadorian swamps there 

 can be no question of crossing, since both, according to Baron von 

 Eggers, belong to one species. Therefore I am inclined to the 

 opinion that whilst the Asiatic Rhizophora displays dimorphism in 

 Fiji, the American Rhizophora displays dimorphism in Ecuador. 

 The reversion on the part of the " Mangle grande " of Ecuador to 

 some of the characters of the Asiatic plant is remarkable, and 

 points to the greater antiquity of the Asiatic R. mucronata as 

 compared with the American R. mangle. 



This accords with the opinion expressed by Schimper in his 

 work on the Indo-Malayan strand flora that the American 

 Rhizophora is either a degenerated descendant of the Asiatic 

 R. mucronata or a sister form derived from a common ancestor. 

 America, as we have seen, possesses only one of the three species 

 of Rhizophora, and this is the only representative that it owns of 

 the four Asiatic genera (Rhizophora, Kandelia, Ceriops, Bruguiera) 

 that constitute the tribe Rhizophorese. The rule prevailing with 

 current-dispersed plants that America is a distributor and not a 

 recipient evidently does not apply to the Rhizophoreae ; and to 

 explain their distribution we must go back to some epoch very 

 remote from the present. That Fiji derived its representatives of 

 Rhizophora mangle from America by the agency of the currents I 

 do not for a moment admit. The restriction of the species and 

 indeed also of the genus to the Western Pacific is very significant. 

 It is far more likely that, as I have pointed out in the case of 

 Lindenia (see page 396), the American Rhizophora was once 

 widely distributed over the tropics of the Old and New Worlds, 

 and that it is now on the " down grade " towards extinction. Its 

 survival in the Western Pacific could thus be explained without our 

 being obliged to suppose that the seedlings or keimlings have been 

 carried uninjured across the Pacific Ocean, an ocean voyage for 

 which, as shown in a later page, they are not well fitted. 



The Occasional Occurrence of more than one Seed in the Fruits of 

 Rhizophora mucronata and Rhizophora mangle {Polyembryony). 



The bilocular ovary contains four ovules, one of which only as a 

 rule becomes a seed. But it is incorrect to say that the fruits are 

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