TO LOWER SIAM. 57 



the eastern coasts of Paliang and in Frovince Wellesley, and 

 have obviously descended from the north along the coast line ; 

 such are Phoenix and Coldenia. 



The list of well known Malayan genera which are appa- 

 rently quite absent from the region north of Alor Sta is very 

 large, but possibly further research might show their presence 

 especially as some of them do occur further north in Burmah, 

 and Assam. A certain number however appear to be entirely 

 absent from any country north of Alor Sta, though common 

 in the Malay Peninsula, and their northern boundary line 

 must be placed here. 



List of genera occurring only north of Alor Sta. 



Cadaba. Distrib. Africa and India. 



Pentacme, Distrib. Siam. 



Pentapetes, Distrib. India. Occurs as an escape from 

 cultivation only in the Peninsula. 



Decaschistia, India and Cochinchina. 



Feronia, India. 



Ochua, India. 



Harrisonia, India. 



Osbeckia, India, Ceylon, China, Cochinchina and 

 Philippines. 



Pleurostylis, India. 



Geissaspis, India. 



Vangueria, India. 



Cystacanthus, Burmah, Cochinchina. 



Bhinacanthus. Africa and India. 



Dicliptera, India, Mala> islands 



Acanthopale, India and Africa. 



Andrograpkis, India and Malay islands (a weed in Penang). 



Barleria, Siam, India, Africa. 



Holarrhena, Burmah and Africa. 



Hcterophragma, Burmah. 



Phylloboea, Burmah. 



Tetraphyllum, Burmah. 



Exacum, Burmah, Borneo, Philippines. 



R. A. Soc, No. 59, ion. 



