665 
chia laurifolia also predominate. The side ridges, as a general rule, consist 
of a series of short, steep inclines with talus slopes at their bases. ‘The tree 
vegetation of the slopes consists of the taller and less xerophytic trees of 
the ridge, together with other species which probably are not able to exist 
on the more exposed places. Near these ridges the tree tops are covered 
with epiphytes, but these become much less common nearer the river bed, 
- where the fog is less dense. In one plot the following trees were noted 
as being common: Hugenia congesta, Hurya acuminata euprista, Adin- 
andra luzonica, Bugenia acuninatissina, Thea montana, and Clethra 
lancifolia; these are intermingled with Pygeum latifolium, Palaquium 
whitfordii, Bugenia bataanensis, Eugenia robertii, Agathis philippinensis, 
Semecarpus sp., and others. In one place, nearly 75 per cent of the 
stand is the myrtaceous J'ristira decorticata. This species is also common 
on and near the top of Limay peak, the vegetation of which is comparable 
with that of the side ridges of the Lamao River, having the same altitude, 
but the extreme summit of this peak itself has only a stunted growth. 
However, while the side ridges present a more mesophytic vegetation, as 
is evidenced by less stunted trees and the xerophytic leaves, the vegetation 
in this situation, owing to the unstable conditions, does not reach the 
luxuriance and the size which it would be expected to have as a result 
of the climate. It is perhaps because of this instability, that more fallen 
trees were noted in this region than on any other portion of mountain, 
although it is one of the surprising features of tropical mountain vegeta- 
tion that very precipitous slopes, having a grade of from 45° to 60°, 
often are covered with a closed forest. Inclines of over 60° so often 
crumble that few trees have a chance to gain anything more than a 
temporary foothold thereon. 
The side ravines near the headwaters of the Lamao River are very un- 
stable. Where signs of ground water near the surface are in evidence, 
species of mosses, liverworts, and ferns are present in such situations, 
although the variety and the number of the individuals are much less than 
they are on the ridges. The very large-leaved fern Dennstaedtia smithti 
and the tree fern Alsophila contaminens are encountered here, the latter 
in the Lamao River canon itself reaching to a height of 8 or 9 meters. 
Cirque-like basins which are comparatively stable appear in many 
places near the upper ends of the side ravines. Groves of Pandanus 
arayatensis are encountered in these situations and here also the tree 
fern Cyathea caudata reaches its largest size, being from 2 to 3 meters 
in height, the large, Lycopodium-like moss, Spiridens reinwardtu, usually 
growing upon it. The undergrowth is characterized by rubiaceous 
species and Hydrangea lobbii. The inside slopes of the crater are even 
more unstable than are those of the Lamao River cahon. Land slips 
are numerous, and comparatively, these sides show but a thin stand; yet 
when looked at from above, the closed forest seems to prevail. This is due 
to the fact that the foliage of the trees on either side nearly meet over the 
