i 



1915.] H. N, Ridley: Botany oj Gtmong Tahan. 137 



Thus the Australian element is larger on Kinabalu than on 

 Gunong Tahan, and it appears to be larger in New Guinea 

 than on Kinabalu. 



On our sea-coasts in the Peninsula we get Spin ifex sqiiarro- 

 sus, Casuarina equiseti folia, Dianella, Melaleuca lettcadendron, 

 Pittosporum fernigineum, Rhodamnia trinervia, Philhydrum 

 lanuginosuin, and several species of Tristania and Helicia. 



On Gunong Tahan at high elevations we find Boeckia 

 frutescens, Leptospermum, Rhodamnia, Tristania, Leucopogon, 

 Pittospoiuui, Helicia, Cryptostylis, Dianella, Gahnia, Schcenus, 

 Lepidosperma, Dacrydiwn. 



In Borneo, besides these plants, we find Driviys, Drapetes, 

 Patersonia, Coprosnia, Trachynicne, Havilandia (a genus allied to 

 the Antarctic species of Myosotis), Euphrasia, and Ranunculus, 

 allied to Australian and New Zealand species. 



Most of these Bornean plants which do not, as far as is 

 known, occur on any of the Malay Peninsula mountains occur 

 only on Kinabalu at a greater altitude than any of our moun- 

 tains rise to, and this is probably the cause of their absence. 



Such of the mountain genera of Australian origin as can 

 thrive near the sea occur in both localities, such as Boeckia on 

 sea-shore rocks in Borneo, Rhodamnia , Tristania, Leucopogon 

 (sea-shores in Singapore and Labuan), Dianella, Gahnia tristis, 

 Schcenus, and Pittosporum. 



One is forced to conclude that at one period there was 

 extending from the Australian region an extensive xerophytic 

 area, which bore an Australian flora. That, probably owing to 

 climatic changes, this flora was swamped by a typical Malay 

 forest-flora of the rain-forest or hygrophjtic t}'pe, so that all 

 that remains to us are such species as could persist in the only 

 xerophxtic regions we possess — the sandy sea-shores and drier 

 mountain-tops. 



The rocks of Gunong Tahan have been examined by 

 Mr. Scrivenor, who considers them to be Estuarine and dates 

 them as having probably been deposited between the Rhsetic 

 and Inferior Oolitic periods. The flora now on this ground, 

 of course, is of much later date than this, but the sands of 

 these ancient Estuarine beds have been much altered, formed 

 into rock and upheaved, and it must have been at a very much 

 later period that these Australian or far Eastern plants crept 

 along over its surface. 



The similar plants occurring on Mt. Kinabalu are believed 

 to have migrated there in Tertiary times (Stapf, ' Flora of Mt. 

 Kinabalu'). 



I would suggest that the history of this flora was 

 somewhat as follows : — 



A big river existed in Northern Pahang, which deposited 

 sand at its mouth which eventually became hardend into rock 

 and elevated as time went on to considerable altitude, and 

 forraed the great mass of mountains kno\An a,s Gunong Tahaii 



