CONTRIBUTIONS 



TO THE 



Flora of Siam 



DICOTYLEDONES. 



Since the time of publication in the Bull. Herb. Boiss. (1904-5) 

 by Dr. F. N. Williams of his " Liste des plantes connues du Siam," 

 our knowledge of the Flora of Siam has made great strides. The 

 penultimate part of the Flora of Koh Chang dealing with the 

 Palmae, Lentibularieae and the Lichenes has appeared. As men- 

 tioned in Kew Bull. 1911, p. 7, Dr. C. C. Hosseus visited Siam in 

 1904-5 and made large collections of plants. Since his return to 

 Europe he has published in various continental magazines a large 

 number of papers dealing with various subjects of scientific interest, 

 and a list of those papers — so far as known to the author — which 

 have a direct bearing on the present contribution will be given in an 

 addendum. 



It might not be out of place to say a few words here on those 

 papers which the writer has found most useful when compiling the 

 present lists. Probably the most important are to be found in the 

 Beihefte zum Bot. Centralblatt — " Beitrage zur Flora Siams " in 

 vol. xxvii., pp. 455-607 and " Die botanischen Ergebnisse meiner 

 Expedition nach Siam " in vol. xxviii., pp. 357-457. The former 

 gives lists of all the plants of certain families known from Siam, but 

 in the latter the author confines his attention to the plants collected 

 by himself and gives a list of nearly all the plants of his own 

 collection. In both papers the author expresses his indebted- 

 ness to various authorities who assisted him in determining the 

 plants. In Engler's Bot. Jahrb., vol. xli., pp. 62-73, Dr. Hosseus 

 gives a list of all the Acanthaceae known from Siam. Most of his 

 plants in this family were determined by the late C. B. Clarke — a 

 recognised authority on Acanthaceae. In the same publication are 

 also to be found " Beitrage zur Flora des Doi Sutap " (vol. xl., 

 pp. 92-99) and " Beitrage zur Flora von Wang Djao am Ma Ping 

 in Mittel Siam " (vol. xlv., pp. 366-374) — two papers dealing with 

 the general aspects of the flora of the regions. Also in Engler's 

 Bot. Jahrb., vol. xli., pp. 55-61, is a description, accompanied with 

 excellent figures and a full discussion on its affinity with neighbour- 

 ing genera, of a very interesting new genus of Rafflesiaceae, called 

 by the author Richthofenia. Reference might be made here to 

 several other papers, but for these the reader must be referred to the 

 list at the end of the present paper. 



The present* contribution may be regarded as a reprint — with 

 additions — of the papers written by the author and published in 

 Kew Bull. 1911, pp. 7-60 and 385-474. As explained there, the 

 primary idea was to give additions to William's list referred to 



