146 



JOUKNAL, K.A.S. (CEYLON). 



[Vol. IX, 



Islands. In that little speck of land in mid ocean, St. 

 Helena, nearly 78 per cent, of the small remnant of its once 

 remarkable flora (i.e., 53 species out of 68) are found 

 nowhere else in the world. Of greater interest and signi- 

 ficance is it when Genera, and not merely species, are endemic ; 

 this, of course, indicates a still further specialization, and 

 here oceanic islands are particularly remarkable. Thus in 

 Mauritius 11 per cent, of the genera are peculiar, and in St. 

 Helena a still larger proportion. 



Now Ceylon, though an island, is by no means an oceanic 

 one ; rather it is what is termed a continental island, being 

 separated from the adjacent continent by the very shallow 

 and narrow piece of sea in Palk Straits. Yet the remark- 

 able fact presents itself that while in Britain probably not 

 a single species is peculiar, here in Ceylon no less than 

 about 800, or more than 29 per cent, of the Phanerogams, 

 are strictly endemic to the island. Indeed, to these would 

 be added by many botanists some 50 more well-marked 

 insular sub-species or varieties of continental species, 

 which would raise the proportion to over 31 per cent.* 

 We do not possess many endemic genera, however— only 

 about 20, or little over 2 per cent. — but here also may 

 be added, as of similar significance; some groups peculiar 

 to the island which are here ranked as sub-genera only. 



How are we to account for this large element of special- 

 ization in our flora ? 



6. The opinions and theories now generally held by 

 naturalists to explain the present distribution of animals 

 and plants over the globe have been expressed and explained 

 in the writings of E, Forbes, Darwin, Bentham, Wallace, 

 J. Hooker, and others. I may remind you of some leading 

 points. Widely distributed as are some species over the 

 world, it is held that each has spread from some single 

 centre where it had its origin, and in cases where a species 

 now exists, not over an unbroken area, but at two or more 

 spots not continuous, and even it may be widely separated 

 from one another, it is considered (when there is no evidence 

 of transport by men or animals) either that these points 



* This is perhaps a larger endemic proportion than is possessed by 

 any other continental island with the exception of Madagascar. 



