1920] Ridley : Peninsular Siamese Plants. 79 



On the 31st March, all our baggage having arrived, we 

 went by train northwards to Koh Lak, or Prachuap Kirikan, 

 in S.W. Siam and in that state we collected for three weeks 

 but the country was so dry and flowerless that no botanical 

 material was obtained. 



I had the assistance of a native collector at Mamoh, 

 Tapli and Tasan and his statements as to the size and nature 

 of the plant from which he obtained his specimens may 

 occasionally be unreliable : colours, however, being noted 

 from the fresh specimens are correct. 



This account is very superficial : it is written merely 

 to give an idea of the localities visited and worked and does 

 not attempt to deal with the flora or fauna of those places. 

 The latter will be recorded in other papers : in this 380 

 plants are dealt with, of which 59 species or varieties are 

 described as new. 



Apparently what Mr. Ridley means in this report by 

 " Malay Peninsula " is not the whole of the Malay Penin- 

 sula, which extends northwards as far as the head of the 

 Gulf of Siam (Lat. 13° 30' N.) ; but only the southern 

 portion below Lat. 7° N., i.e., practically the Malay States : 

 but exclusive of the Malay district of Perils and inclusive 

 of the Siamese State of " Patani." 



The northern limit of the true Malaysian flora, which 

 covers the southern half of the Malay Peninsula, Sumatra, 

 Borneo and — to a less extent — Java, and of which the con- 

 tinental section may be called Malayan, seems to be a line 

 joining the towns of Alor Star (in Kedah) and Singgora 

 (at the entrance to the Inland Sea) . 



Botanical features confirm what geological investiga- 

 tions indicate — that this boundary was the coast line of what 

 was once an island but what has since become the southern 

 half of the Malay Peninsula. ^'^ 



I would call this Alor Star — Singgora hue a major 

 transverse break in the Malay Peninsula and am inchned 

 to think that there is another between Bandon and Pangnga, 

 and perhaps Bandon and Trang. 



The pass across the Isthmus of Kra, between Pakchan 

 and Chumporn, to which so much attention has been given, 

 is a mere dip in the mountain range there and seems to be 

 structurally and biologically of very little importance. 



Mr. Ridley elsewhere calls the flora of Peninsular Siam 

 the " Tenasserim Flora " and the choice of the name seems 

 a reasonable one ; for though the area in which it occurs is 

 politically Siam yet the plants of a great part of that State 

 are much the same as those of Tenasserim and the flora of 

 the latter region was by a long period the first to be investi- 

 gated and known. 



10 Scrivenor, Journ. Straits Branch Roy. Asiat. Soc. No. 59, July igii, 

 "The Geological Structure of the Malay Peninsula," pp. 1-13 (vide pp. 

 2,8,9.). 



Kidley, torn, cit., "The Flora of Lower Siam," pp. 15-26 (vide pp. 

 15, 16,); id.ib., " A Botanical Expedrtion to Lower Siam, " pp 37-60 (vide pp. 

 27, 29, 30, 55, 56, 59, 60). 



