1890.] D. Prain — The non-indigenous species of the Andaman Flora. 253 



Names of Species. 



Remarks. 



110 Ischaemum rugosum Nees. 

 I. ciliare Retz. 

 Anthistiria scandens Roxb. 

 Chloris barbata Sw. 

 Eragrostis unioloides Nees. 



Aberdeen. 



Aberdeen, rather common. 

 Aberdeen, very common. 

 Ross Island and Aberdeen. 



Very common on Ross Island, not seen at 

 Aberdeen. 



115 f Selaginella proniflora Bah. 



w 



I 



§>-{ Cheilanthes tenuifolia Shv. 

 "ja, | Ceratopteris thalictroides 

 Brogn. 



I 



Very plentiful everywhere on Ross, bnt not 

 present either at Aberdeen, Hopetown or 

 Viper. 



On gravelly roadsides at Aberdeen. 



In ponds at Aberdeen ; possibly introduced by 

 water-birds ; (see note on Monochoria vagin- 

 alis.) 



Comparing the state of affairs in 1866 with that prevailing in 1890 

 we find that at the former date there were present in the Andamans 61 

 weeds of cultivation of which 58 were again met with, either in Novem- 

 ber 1889 or in April 1890. But too great weight should not be placed 

 on the absence of any plant, since it is quite possible that in visits of 

 such short duration as those of the writer and Dr. King species that 

 are not very common might easily be overlooked. 



In November 1889 and in April 1890, on the other hand, we find 

 that not only were 58, or 95 °/ , of the weeds of 1866, present, but that 56 

 others had found their way into the settlement during the interval be- 

 tween 1866 and 1890. 



Briefly reviewed the results indicated by these four lists are : — 



1. That in 1866 15 intentionally introduced plants and 61 weeds 

 of cultivation had apparently or actually become so established in the 

 Andamans that, though not indigenous plants, they had become an 

 integral portion of the Andamans flora. 



2. That by 1890 14 more of the plants intentionally introduced 

 prior to, but only seen under cultivation in, 1866 had become similarly 

 naturalised ; that along with these 9 species, intentionally introduced 

 during the interval between 1866 and 1890, had begun to appear spon- 

 taneously ; also, that during the same interval 56 more weeds had been 

 introduced. 



3. That, on the other hand, a species appearing spontaneously in 

 1866 was only seen cultivated in 1890, and that three of the 1866 weeds 

 were not met with in 1889 or 1890. 



The subjoined table exhibits the intrusion of the non-indigenous 

 element at present existing in the flora of the Andamans. 



