es EO FS 
410 The Philippine Journal of Science 1914 
pearance of a dense stand, even at first, but the grass appeared 
in definite, well-separated bunches, by whose development an 
ordinary stand is being built up. This is taking place measur- 
ably faster at lower elevations, as one would naturally expect, 
with the chance to obtain more water through seepage. Inves- 
tigation of the root system of a number of plants of Saccharum 
seemed to indicate that they were of recent origin and could not 
have been developed previous to the eruption. 
At higher altitudes Saccharum forms compact, somewhat 
dwarfed bunches, widely separated on the sides of the ridges 
near the heads of drainage channels. At lower elevations the 
bunches occur nearer together until a fairly dense stand occupies 
the lower slopes, yet even in these places the great growth 
activity has not yet succeeded in obliterating the bunch-grass 
habit and covering the ground. 
The outposts of Saccharum in both directions indicate that 
the consocies is tending to spread both up the ash slope to the 
crater rim and out on the flats close to the level of Lake Bombon. 
As the ground is so open, it can readily do this and real com- 
petition for the ground has hardly begun. Secondary species, 
at best very few in this consocies, are even fewer here on Taal, 
being more frequently represented by Desmodium triflorum than 
by any other. In the ecological center of the area occupied by 
this consocies the association of grasses is closed against ecolog- 
ically inferior species by the dense growth of the grass. Any 
other species growing there must do so in successful competi- 
tion against the grass. Quite naturally such species would be 
most likely to be shrubs or trees. Such are present, nowhere yet 
in very great numbers in most parts of the island, but thoroughly 
well scattered and thriving. 
As an invading association it has virtually no plants to contend 
with, only the edaphic conditions of the situation. Working 
toward the crater rim there is no competition and it is merely 
a matter of time until the invasion of the slopes is entirely 
accomplished. On the flats, where the soil is nearly water- 
soaked, Saccharum occupies only little ridges or higher spots in 
the flat. In wet ground it cannot displace Phragmites, and con- 
sequently reaches its limit. EXverywhere else Saccharum is the 
most important pioneer species in the open ashy ground. UI- 
timately it should be replaced by shrubs or trees, but for a long 
time it will remain represented as part of a mixture, ecologically 
inferior to the shrubs and trees, but on the ground ready to take 
advantage of any opening afforded. 
