150 D. Prain — The non-indigenous species of the Ajidaman Flora. [April, 



II. Species under cultivation, obviously planted, or intentionally- 

 introduced seen in 1889, not present in 1866, 42 in all, bringing the 

 total of voluntarily introduced species up to 165. 



[The species of these sub-lists consist of ; — 1, — such as probably 

 never could become naturalised, (these were indicated in the lists as 

 exotic by a distinctive mark) ; 2, — those that might be expected to hold 

 their own in the struggle for existence if the settlement should happen 

 to be abandoned; and 3, —those that are naturalised in the Andamans 

 now. The second category cannot be limited from the first without 

 individual differences of opinion arising as to its exact components ; it 

 is, however, of necessity that from which the third is being steadily 

 recruited.] 



III. S^Decies unintentionally introduced prior to 1866, 60 in all ; 

 and 



IV. Species unintentionally introduced between 1866 and 1889, 

 44 in all ; making a total of involuntarily introduced species up to 

 Is'ovember 1889 of 104. But 5 of the species present in 1866 were 

 not met with in November 1889, and 3 of those met with being 

 cryptogams were omitted from the calculations which were confined to 

 flowering plants only. 



The results indicated by the 4 sub-lists were : — 



1, — that, in 1866, 15 intentionally introduced plants and 60 weeds 

 had actually or apparently become established in the Andamans and, 

 though not indigenous plants, had become an integral portion of the 

 Andaman flora. 



2, — that, in 1889, 14 more of the plants intentionally introduced 

 but only seen under cultivation in 1866 had become naturalised ; that 

 along with them 7 species intentionally introduced during the interval 

 between 1866 and 1889 had begun to appear spontaneously ; also that 

 during the same period 41 more weeds (phanerogamic) had become 

 introduced. 



3, — that on the other hand one species that was appearing sponta- 

 neously in 1866 was only seen cultivated in 1889, and 5 weeds that were 

 seen in 1866 were not met with in 1889. But too great weight was not 

 laid on the latter fact, which might well be the i"esult of the shortness 

 of the 1889 visit (5 days only). 



The remaining portion of the paper was occupied with an enquiry 

 into the rate of naturalisation and the nature of the naturalised speciea ; 

 — the results may be briefly stated. 



1. The total number both of naturalised and of unintentionally 

 introduced species constantly increases. 



2. The rate of naturalisation of intentionally introduced species 



