16,4 McGregor: Some Features of the Philippine Ornis 387 
can be distinguished; namely, mangrove, beach, dipterocarp, 
molave, pine, and mossy forest. 
The mangrove forest is distinct; it is important as a source 
of firewood and tanbark and is interesting because of its plants, 
but it harbors few birds. The beach forest has been largely 
destroyed and is of little interest for its birds. The dipterocarp 
forest covers the largest area and is the most important as a 
source of lumber ; all of its birds and plants are of much interest. 
Much of the molave forest has been destroyed; zoologically it 
scarcely differs from the dipterocarp forest. The pine forest is 
found in restricted areas in Luzon and Mindoro. The mossy 
forest is found on several islands at high altitudes; its trees 
are almost worthless for lumber. The species of plants and 
animals of the pine forest and the mossy forest are much fewer 
than those of the dipterocarp forest, but they are of very great 
interest to the naturalist. 
MANGROVE TYPE OF FOREST 
The mangrove type is literally a forest in the sea. Where 
conditions are favorable it occupies beaches washed by the tides. 
It is especially well developed on mud flats at the mouths of 
rivers that enter the sea at the heads of protected bays. Wher- 
ever wave action allows a fairly stable shore line, trees of this 
type are present. They occur on the quieter portions of coral 
reefs and may be the only indication of slightly submerged reefs ; 
in such cases what appear at a distance to be forested islands are 
found to have no land exposed except perhaps at the lowest tides. 
Most of the trees in mangrove forests belong to the family 
Rhizophoracese and include the following species: 
Rhizophora mucronata Lam. Bruguiera cylindrica (Linn.) Blume. 
Rhizophora conjugata Linn. Bruguiera parviflora W. & A. 
Bruguiera gymnorhiza Lam. Ceriops tagal C. B. Rob. 
Bruguiera eriopetala W. & A. 
Species of other families that are characteristic of the man- 
grove type of vegetation include: 
Sonneratia pagatpat Blanco. Xylocarpus granatum Koen. 
Avicennia officinalis Linn. Excoecaria agallocha Linn. 
Lumnitzera littorea (Jack.) Voigt. Heritiera littoralis Dry. 
Xylocarpus moluccensis (Lam.) M. 
Room. 
Although this type of forest, from the nature of its habitat, 
is free from undergrowth it is difficult to make one’s way through 
a typical stand because of the complex and tangled system of stilt 
roots of the species of Rhizophora, the dominant species in these 
