28 HISTORY OF SANTUBONG, SARAWAK. 
_ down by the Sarawak river. The flora of this swamp presents 
no features of special interest and as such swamps have been 
so often described we shall only give it passing mention. In 
the northern half of the island on the west side there is a 
small swamp which well illustrates the mode of formation of 
such muddy areas. Into it there flows a large stream which 
drains the western slopes of the mountain and thus brings 
down disintegrated rock and earth to be eventually deposited 
near the mouth of the stream. The extension seawavrds of 
such a mudflat is limited by the violence of the waves and in 
the small swamps in question we find that in spite of the 
continual influx of fresh earthy material from the mountain, 
the swamp is confined to the interior of a small sheltered bay. 
In every part of the swamp the mud is beset with numerous 
elose-set uprising shoots and aerating roots of the trees growing. 
therein and at the sea margin of the swamp these short rigid 
shoots form a dense fringe round which the mud collects to 
form a bank which can resist the onslaughts of the waves. 
The tree which leads the way in this marine encroachment is 
the ‘Pirapat’ (Sonneratia alba)—often accompanied by the 
Aegiceras majus—and when once this has obtained a firm hold, 
other swamp trees appear. In the small swamp we are con- 
sidering the ‘Pirapat’ and the Aegiceras are most abundant 
but in addition we have also ‘Bako’ (Phizophora nucronata 
and R. conjugata), ‘Tengah’ (Ceriops candolleana), © Putut’ 
(Bruguiera sp), Apiapi’ (Avicennia officinalis) and ‘Taruntum’ 
(Lumnitzera coccinea). 
In the southern half of the island the characteristic trees of 
the mangrove vegetation are the Bakos (Bako jangkar is Rhzzo- 
phora conjugata and Bako gaiong is rhizophora mucronata), 
the Putut, the “Aleh aleh’ (Kandelia rheedit), the Api api, 
¢the ‘Nireh’ (Carapa moluccana) and the Nipah palm which 
however only reaches a strong development: in parts where 
the mud is relatively firm and where the tidal forces are not 
too strenuous. 
The geographical relations of a mangrove swamp situated 
in the delta of a tidal river are continually changing. Not 
only are new channels being formed and old ones being silted 
Jour. Straits Branch 
