204 FRANK C. GATES 



present on Mount Makiling, 34 km. to the northeast, but seed- 

 ing takes place during the southwest winds. The heavy seeds 

 of the dipterocarp, Parashorea plicata Brandis have been found 

 a httle over a kilometer from the nearest parent tree, but could 

 no doubt be carried considerably further in severe, typhoon 

 winds. 



Bubbling areas and the increase in temperature of the crater 

 lake are positive evidence that Taal is still a live volcano and 

 that vegetation may again be compelled to commence with bare 

 ground. 



STRUCTURE OF THE VEGETATION 



The nine plant associations on Taal Volcano may be grouped 

 in three genetic series 



The Aquatic Series. This series, in which aquatic plants tend 

 to build up the bottom of a body of water, was poorly repre- 

 sented in a few places by the VaUisneria Association. In rooted 

 plants of VaUisneria gigantea, such floating plants, as Cerato- 

 phyllum demersum, Pistia stratiotes and Lemna trisulca, were 

 frequently enmeshed. 



The Marsh Series. This series inhabiting wet ground in pro- 

 gressively drier stages to dry ground is clearly indicated in a few 

 places on the island, but nowhere is either well developed or 

 extensive. The Cynodon, Panicum repens, and Phragmites 

 Associations are present. 



The Dry Ground Series. To this series belong the associations 

 which form 98% of the vegetated area of the island. Four 

 formations may be easily recognized. The Strand Formation, 

 represented by the Ipomoea pes-caprae and Sesbania associa- 

 tions, occurs quite frequently on the beach. The physiological 

 requirements of the plants keep them down close to the water 

 edge, although there are seldom any plants immediately in 

 back of them to keep them from spreading up beyond the strand. 



The Cogonal or Grassland Formation is the best developed and 

 most extensive on the island. The Cogon Association, in one or 

 another of four consocies, is the pioneer association in the re-, 

 vegetation of the greater part of Taal Volcano. The Saccharum 



