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420 The Philippine Journal of Science 1914 
Species of plants in the parang association—Continued. 
INVADING SPECIES. 
Albizzia procera. Ficus hauili. 
Allaeanthus luzonicus. Litsea glutinosa. 
Alstonia scholaris. Maesa cumingii. 
Arenga sp. Mallotus moluccanus. 
Artocarpus nitida. Melicope triphylla. 
Bambusa blumeana. —. Oroxylum indicum. 
Ceiba pentandra. ; Premna nauseosa. 
Celtis philippensis. Sterculia foetida. 
Cratoxylon blancoi. Vitex parviflora. 
Eugenia jambolana. Wrightia laniti. 
THE LOW ALTITUDE TREE FORMATION 
THE BAMBUSA-PARKIA ASSOCIATION 
This very typical association, formerly well represented on 
Taal Island especially in the northern part, as well as upon 
all the adjacent islands, now occurs on Taal Island on the north- 
eastern cape and on Mounts Binintiang Malaki and Balantoc 
in the northwestern region. The bamboo growth form—tall, 
treelike grasses—is a characteristic part of this association. It 
mixes, or alternates, with the Parkia type—-moderately tall trees 
which are either deciduous or have their transpiration surface 
materially reduced for a part.or all of the dry season. The 
bamboo element is represented on Taal by Bambusa blumeana on 
the slopes of Mounts Pirapiraso and Bignay in the northeast 
and at the foot of Mount Balantoc near Panipihan in the 
northwest. The bamboos must have regenerated from root- 
stocks beneath the mud and ashes for there has been no recent 
seeding of this species. Spreading by purely vegetative means 
is very slow. It will take a very long time for the bamboo 
thus to occupy the land apparently very suitable for it. Bam- 
busa readily displaces any of the parang trees, forming a 
thicket of such density that but very few secondary species of 
minor importance can develop. The bamboo can be displaced 
only at higher elevations where conditions are less suitable for it. 
While Parkia timoriana, itself, has not yet invaded the island, 
its growth form is represented by other species, particularly 
Albizzia procera, Oroxylum indicum, Alstonia — scholaris, 
Wrightia laniti, Eugenia jambolana, Ceiba pentandra, Sterculia 
foetida, Celtis philippensis, Mallotus moluccanus, and Ficus 
haut. For a complete list of the species so far present the 
reader will note the species listed as invading the parang. Some 
of these trees invade the grassland and others the parang, but 
seldom do any of them invade unvegetated ground. Their re- 
