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but in these cases, owing to the fact that the breaker line is far distant 
from the shore, an area of more or less quiet water intervenes. Wave- 
cut terraces may be produced at the bases of sea cliffs, and these are often 
so covered with large boulders as to leave places between the latter fairly 
well protected from the heavy action of the waves, when the terrace is 
submerged at high tide. In a word, because of the absence of strong 
waves, the physiographic situations which have been discussed offer a 
favorable place for the establishment of plants. In the Tropics, these 
places are occupied by the well-known Mangrove and Nipa formations. 
Within the limits of the Reserve there are three physiographic situa- 
tions, but, because of the precipitous nature of the coast and the small 
size of the rivers, there is only a weak development of the Mangrove and 
Nipa formations. The first stages of the life history of the swamps 
produced by these plants are here encountered. 
(a) The Mangrove and Nipa-Acanthus formation behind sandy 
beaches.—Situated at the mouths of the Lamao and Limay rivers, there 
are small areas having the Nipa-Acanthus formation. Although the 
species comprising this are most in evidence, yet the elements of the 
mangrove formation are not lacking... The early stages in the develop- 
ment of the vegetation on the strand below high tide and behind beaches, 
usually show among the first arrivals Nipa fruticans (see Pl. XI), the 
most important plant of the Nipa-Acanthus formation. The fruits of 
this palm have a remarkable capacity for being carried through dong 
distances by shore currents. It is not an uncommon sight to see germi- 
nated seeds floating in the water near the beach, or lying on the latter 
where they have been cast up by the waves but where the dynamic condi- 
tions on the strand are too strenuous to admit of their obtaining a foot- 
hold. However, if they are carried into lagoon or tidal channels by the 
flow of the tide, then in these more quiet waters young plants of this 
species find a favorable place for development. Thus, newly formed 
lagoons have Nipa fruticans among the first pioneers, although, in many 
instances, grasses and sedge may precede the Nipa stage. 
Plate XL shows a condition in which Panicum repens, Fimbristylis 
ferruginea, and Cyperus malaccensis form the brackish meadow. Such 
habitats are usually rapidly replaced by the more shrubby growths of 
several other plants, among which the shrubby creeper Acanthus ilict- 
folius, the hard, prickly, ilex-like leaves of which give a decided character 
to the formation, may be mentioned. Often, the legumes Derris uligi- 
nosa, Caesalpina nuga, and Dalbergia torta, all of which have their origin 
in soils less salty than that in which Acanthus grows, are entangled 
with the latter and with it, because of their scandent habit, they form 
dense, jungle-like and thorny thickets, which are difficult to penetrate. 
The ground rosettes of the fern Acrostichum aureum and the amaryll- 
idaceous Crinum asiaticum are scattered here and there in the open 
43814—7 
