151 



tutes the predominating element in the woody vegetation of 

 Aldabra botli as to number and diversity of genera and number 

 of species; but probably they are not so conspicuous, even collec- 

 tively, in the scenery as the Mangroves, the Figs and Euphorbia 

 Abbottii. 



The conspicuous coco-nut plantations are purposely left out of 

 consideration. There are 15 species of Aldabra liubiaceae, 

 belonging to 10 genera, of which 5 range beyond the African 

 region, and 1, the large genus Psychotria, is common to the 

 tropics of both hemispheres. Polysphaeria, Triainolepis, 

 Rittidea, Tarenna and Tricalysia are limited to the African 

 region, including Madagascar and the Mascarenes. 



A list of certainly introduced plants collected in Aldabra is 

 given in a preceding section. It is not offered as exhaustive 

 and calls for no special remark except that there is no evidence 

 of any of these ^plants being common or over-running the island. 



Particulars are given in a condensed form of the Flora of the 

 islands of Assumption, Cosmoledo, Astove, Fa rquhar, Provi- 

 dence, St. Pierre, Gloriosa, Amirantes, Coetivy, Agalega, Car- 

 gados Carajos, the Laccadives, Maldives and the Chagos Archi- 

 pelago; affording data for some interesting comparisons. 



The list of plants occurring in these islands (excluding Car- 

 gados, the Laccadives, Maldives and Chagos) and hitherto not 

 found in Aldabra is perhaps the most interesting feature. It 

 consists of 23 species, of which about half are widely spread 

 littoral and insular plants, accidentally absent from Aldabra, or 

 used up by 'the settlers for fuel or building purposes; for 

 example, Ajzelia bijuga, Terminalia Catappa, Barringtonia 

 speciosa, Ochrosia borbonica and Hernandia peltata. In a 

 different category belong Hisbiscus Hornei, Chralis sp. Hippo* 

 cratea sp., Bre&ia, Nesogenes prostrata and Disperis; but they 

 are all plants of the region outside of these islands. 



In conclusion, the data collected point clearly to a common 

 origin of the Flora of Aldabra and the neighbouring islands; and 

 that flora is essentially African, and almost without any infusion 

 of an Asiatic element, or, to be more precise, Malayan element. 

 By Malayan element I mean the presence of representative, 

 species of such genera as Nepenthes and Amaracarpus 

 (liubiaceae), which have their greatest concentration in Malaya. 

 Such an element exists in the Flora of Seychelles and in the 

 Mascarene Flora; but it is difficult, indeed impossible, to esti- 

 mate the relative importance of the various elements of a flora 

 in attempting its history- It is easy to compile lists of plants 

 and show their present distribution : but how and in what direc- 

 tion this distribution has been effected is beyond the wisdom of 

 man to fix from available date. It is easy to generalise and 

 theorise, and it is easy to speculate on the course of evolution 

 and the sequence of changes in vegetation; but a satisfactory 

 history of events is perhaps unattainable. Indeed, the more I 

 learn of the present distribution of plants the more I am puzzled 

 as to how it has been brought about. Of course, there is no 

 disputing the fact that much has been accomplished and placed 

 beyond doubt, but much more remains to be discovered before 

 we can arrive at satisfactory results. Taking the Flora of 





