149 



Dis peris tripetaloides — Agalega. 

 Fimbristylis exilis — Assumption. 

 Eriocliloa subulifera — Assumption. 

 Stenotaphrum clavigerum — Assumption . 

 Panicum as sumption is — Assumption. 

 Dactyl octenium pilosum — Assumption. 



With some noteworthy exceptions* the plants in the preceding 

 list are regional and also occur either in Seychelles or in the 

 Mascarenes, or in both groups. Nesogenes prostrata is appar- 

 ently confined to Agalega, as well as Pipturus argenteus> it this 

 be really specifically different from P. incanus. 



Desmanthus virgatus is an American colonist. The Disperis 

 is also recorded by Baker from Mauritius and Bourbon. 



From the general distribution of these twenty-five species of 

 plants, their absence from Aldabra may be considered as acci- 

 dental. The arboreus Afzelia bzjuga, Tenninalia Catappa, 

 Barringtonia speciosa, Ochrosia borbonica and Hernandia peltata 

 may have fallen before the axe in Aldabra for building purposes. 

 Other woody species may have been used up for fuel, while a few 

 inconspicuous herbs may have escaped the eye of collectors. 



Summaky. 



For convenience it may be repeated here that Aldabra is an 

 atoll, similar in size to the Isle of Wight, being approximately 

 22 miles by 8. It is oblong-oval in outline and the land rim 

 is broken up into 4 islands of very unequal size. The lagoon is 

 about 20 miles by 6, and contains numerous small islands. In 

 area the atoll is about 120 square miles, of which about half is 

 lagoon, and the surrounding land rim is from 12-15 ft. above 

 high water line, 



Aldabra is situated some 600 miles from the Seychelles Archi- 

 pelago, 400 from East Africa, and 240 from Cape Amber, the 

 nearest point of Madagascar, with a number of similar atolls and 

 coral reefs to the immediate east. Assumption, the nearest 

 island, is about 20 miles distant, but this is exceptional in 

 not being a true atoll, having no central lagoon. 



All writers agree that Aldabra is densely clothed with vege- 

 tation, and my task of classifying the various collections brings 

 to light the fact that this vegetation is unusually rich and varied 

 in elements for an atoll flora, and comprises herbaceous, shrubby 

 and arboreous species. Excluding species evidently introduced 

 through human agency, direct or indirect, but including a 

 number of uncertain arrival, the Flora of Aldabra comprises 

 over 170 species of flowering plants and one fern — Acrostichum 

 aurenm. This fern is almost cosmopolitan in tropical salt 

 marshes, including Seychelles and the Mascarenes, but it has not 

 been observed in any of the other small islands dealt with in 



* The occurrence of four endemic grasses in Assumption is remarkable. 

 Of these Eriochloa suhulifera is an African or in a wider sense an Indo- 

 Africau type, whilst Stenotaphrum claviaerum has its nearest ally in 

 MadayrascHr (S. oo*fa<-h<jum, Rak.). and Panicum assumptionis in Italian 

 Somaliland (P. pinifolia, Chiov.). Dartijloete«ium pilosum is a very marked 

 member of the group represented by I), aegyptiacum, Wilid. — O. S. 



