THE FLORA OF MANILA. 207 
which lack this character, and helps to account for the wide and 
rapid distribution of tropical weeds. 
SUMMARY. 
1. The original vegetation of the Philippine Archipelago was 
undoubtedly a continuous forest of one type or another. The 
present enormous deforested areas, cultivated and fallow lands, 
thickets, second growth forests, and open grass lands are directly 
or indirectly due to the presence of man. The original forests 
have been destroyed by crude methods of agriculture and recur- 
ring grass fires in abandoned clearings. 
2. Most of the species found in the settled areas, that is, light- 
loving species adapted to growth in the open, and which cannot 
withstand forest conditions, must have been introduced into the 
Archipelago after the advent of man, and after the nature of 
the vegetation had been altered over greater or less areas. 
These species cannot persist and reproduce themselves in forests. 
3. A high percentage of the species in the settled areas have 
been introduced into the Philippines some through natural agen- 
cies and very many purposely or inadvertently by man. Many 
of these species reached the Archipelago in prehistoric times, 
while many others have been introduced since the advent of the 
Europeans. 
4. Practically all the useful plants in the Philippines, exclud- 
ing the forest trees, the rattans, some bamboos, a few palms, and 
the abaca plant {Musa textilis Nee) have been purposely intro- 
duced from other countries. These introduced economic plants 
include all the important species yielding food, the cereals, nearly 
all the fruit trees, condiments, many medicinal plants, and most 
of the commonly cultivated ornamentals. Many were introduced 
in prehistoric times, chiefly from the Malayan region, but a 
high percentage have been introduced within the past 400 years, 
including a great number of American origin. 
5. The percentage of endemism in regions where the original 
forests have not been disturbed by man is over 40 ; in the settled 
areas and in those regions where the forests have been destroyed 
it is but about 12. 
6. Of the 1,007 species found in the vicinity of Manila, a 
region where the original vegetation has been largely destroyed 
by man, about 550 are indigenous, and 475 introduced. Of the 
introduced species over one-half, or 232, are spontaneous; 225 
are found in cultivation only, or but sparingly spontaneous. 
7. As to the ranges of these 1,007 species, 812 extend to the 
