Journal of the Federated Malay States museums - Sabrizain.org

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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 equisetifolia, 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 mountains
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