1890.] D. Prain — The non-indigenous species of the Andaman Flora. 235 



1st, 1848, he found the temperature to be ouly 104° F. # These remark- 

 able fluctuations in the temperature of Sita-kund are well deserving 

 of further inquiry, and Sita-kund is so accessible to residents at Mungir 

 that frequent thermometric observations could readily be carried out 

 there. Several irregular observations by Mr. Masters on the hot springs 

 of the ISTamba forest in Assamf also indicated considerable fluctuations 

 in the temperature of those springs at different seasons. 



The spi-ings above described, together with some others already 

 published, form two well-marked chains running parallel to one another 

 in a direction from S. W. to N. E. — the one series being found along 

 the southern flank of the Santal Pargana Hills, and the other about 95 

 miles further north, in the Kharagpur Hills and chiefly along their 

 southern flank. It is interesting to find historic testimony to the 

 former existence in this latter region of an active volcano : the Chinese 

 pilgrim, Hiuen Tsiang who visited the neighbourhood of Mungir about 

 "the year 634 A. D. records J that " by the side of the capital and bor- 

 " dering on the Ganges river is the I-lan-no mountain, from which is 

 "belched forth masses of smoke and vapour which obscure the light of 

 " the sun and moon." 



XIII. — Natural History Notes from H. M.'s Indian Marine Survey 

 Steamer " Investigator," Commander R. F. Hosktn, R. N., Com- 

 manding — No. 16. The non-indigenous species of the Andaman 

 Flora.— By D. Prain. 



[Received 28th February 1890 ; Read 2nd April 1890.] 



The non-indigenous element in a flora — the weeds of cultivation 

 and the cultivated plants — species introduced, involuntarily or inten- 

 tionally, by man — is not often dealt with apart, since weeds are rarely in 

 themselves interesting, and because a local treatment is hardly satis- 

 factory where cultivated forms are concerned. But the intrusion of 

 this element is a subject of peculiar interest, particularly when it is 

 possible to review it historically, and as opportunities for doing this are 

 rare, it is well to make use of all that occur. 



The Indian convict settlement of Port Blair in the Andaman 

 islands affords such an opportunity. This settlement was commenced 



* Himalayan Journals, I, p. 89. 



f Reported by Dr. Prain in the Society's Proceedings for 1887, p. 201. 

 % Si-yu-U, translation from the Chinese of Hiuen Tsiang by S. Beal, II, p. 187. 

 31 



