392 
Philippine Journal of Science 
1920 
temples. Some are almost cylindrical, rising up out of the ground as if 
their bases were concealed by accumulations of the soil; some get much 
thicker near the ground like our spreading oaks; others again, and these 
are very characteristic, send out towards the base flat and wing-like 
projections. These projections are thin slabs radiating from the main 
trunk, from which they stand out like the buttresses of a Gothic cathe- 
dral. They rise to various heights on the tree, from flve or six to twenty 
or thirty feet; they often divide as they approach the ground, and some- 
times twist and curve along the surface for a considerable distance, 
forming elevated and greatly compressed roots. These buttresses are 
sometimes so large that the spaces between them if roofed over would 
form huts capable of containing several persons. Their use is evidently 
to give the tree an extended base, and so assist the subterranean roots 
in maintaining in an erect position so lofty a column crowned by a broad 
and massive head of branches and foliage. Aerial-rooted forest trees 
* * * and the equally remarkable fig-trees of various species, whose 
trunks are formed by a miniature forest of aerial roots, sometimes separate, 
sometimes matted together, are characteristic of the Eastern tropics, 
* * *. The leaves of the Asiatic caoutchouc tree (Ficus elastica), 
so often cultivated in houses, is a type of this class (trees with large, 
thick, and glossy leaves), which has a very fine effect among the more 
ordinary-looking foliage. Contrasted with this is the fine pinnate foliage 
of some of the largest forest trees, which, seen far aloft against the sky, 
looks as delicate as that of the sensitive Mimosa. The great trees we 
have hitherto been describing form, however, but a portion of the forest. 
Beneath their lofty canopy there often exists a second forest of moderate- 
sized trees, whose crowns, perhaps forty or fifty feet high, do not touch 
the lowermost branches of those above them. * * * Yet beneath this 
second set of medium-sized forest trees there is often a third undergrowth 
of small trees, from six to ten feet high, of dwarf palms, of tree-ferns, and 
of gigantic herbaceous ferns. Yet lower, on the surface of the ground 
itself, we find much variety. More frequently it is covered with a 
dense carpet of selaginella or other lycopodiaceae, and these sometimes 
give place to a variety of herbaceous plants, sometimes with pretty, but 
rarely with very conspicuous flowers. 
BIRDS OF THE LOWLAND FORESTS 
In the lowlands of any island it is the old uncut forest, more 
or less similar in character to the tropical forests described by 
Wallace or the dipterocarp and molave forests described by Whit- 
ford and by Brown, that will harbor the endemic species of birds 
if there be any. Unless it is desired to accumulate a series of 
specimens of widely distributed species, it is almost a total 
waste of time to collect in grassland or second-growth thickets. 
In investigating the avifauna of an island that is ornitholog- 
ically unknown, the main effort should be expended in reaching 
primary, uncut forest — on level ground, if possible, and as 
By primary forest I mean the original natural forest of the lowland 
in distinction from grassland, second-growth thickets, coconut trees and 
other planted vegetation, the beach type, and the mangrove forest. 
