412 The Philippine Journal of Science 1914 
of shrubs and trees, especially Albizzia procera and Sterculia 
foetida, have come in. It appears that the parang and tree 
species will keep on increasing in number and importance and 
will come to occupy a great deal of the ground now dominated 
by Themeda. Unless a dense mountain forest should develop, 
however, it seems improbable that Themeda will be driven from 
the steepest slopes for a long time. 
The Imperata cylindrica consocies.—The third of the important 
consocies represented on Taal Island is dominated by cogon 
or lalang grass, Imperata cylindrica koenigii. This grass is very 
abundant on the mainland in all directions from the volcano, and 
its very light, very numerous seeds are so easily carried to the 
island that it is a wonder that this consocies is not extensively 
present on the island, instead of being so limited in distribution. 
Although a few individuals of this grass species occur in a 
number of habitats on the island, as an association its distribu- 
tion is limited to the region back of the bay near Pirapiraso. 
Previous to the eruption this grass was fairly abundant in the 
parang land. The area that it now occupies, barring fires, will 
become parang in the near future, but at present there are 
some areas that are characteristically grass. The consocies 
occupies the crests of ridges for the-most part, although it is 
well developed in the wide, shallow valley reaching back from 
Pirapiraso, in land that was more or less in cultivation previous 
to the eruption. 
The structure of the association is in every way typical of 
its normal appearance, that is, a compact close “sod” develop- 
ment of grass covering the ground, excluding species ecologic- 
ally inferior and often ecologically superior ones also. In the 
grassland, especially toward the edges are shrubs and small 
trees, which clearly indicate the fate of this association under 
undisturbed dynamic conditions. In case of the frequent occur- 
rence of fires, this association can maintain itself against the 
shrubs and trees, which otherwise will soon come to dominate. 
Fires may be set more or less willfully either by tourists or 
fishermen. 
The only open ground within reach of this association is 
the beach and the flats, which this association does not ordinarily 
invade. Therefore, in so far as the least devastated region of 
the volcano is concerned, this consocies is occupying virtually 
its maximum area. Further area can be gained only through 
accident to the woody vegetation. In the absence of disturbance 
the area of this consocies will gradually decrease, possibly to 
