THE FLORA OF MANILA. 
173 
fact that so few species of American origin have reached PoHllo 
in the past 375 years, leads us to infer that very many of the 
species of oriental or of unknown origin that for the most part 
are now cosmopolitan in the tropics, which like those of known 
American origin are comparatively few in Polillo, have reached 
the Philippines since the advent of the Europeans. 
Not only does the vegetation of the small and medium-sized 
islands bear out the theory that very many of our characteristic 
open country species are of recent introduction, but the condi- 
tions in some parts of the larger islands are practically the same. 
In the Province of Bataan, just across the bay from Manila, and 
only about 35 kilometers distant, a fairly intensive study has been 
made of a strip of land extending from the seashore to the summit 
of Mount Mariveles, attaining an altitude of about 1,400 meters.^ 
While most of the area is covered with primeval forest, still a 
strip along the coast, several kilometers in width, consists of open 
lands, low thickets, etc., with climatic conditions closely approxi- 
mating those in Manila. This coastal strip has at one time or 
another been entirely deforested, but is now, except for small 
cultivated areas and open grass lands, covered with second growth 
forest, thickets, etc. This region yielded 1,114 species of flower- 
ing plants and vascular cryptogams, and of this number only 90 
are supposed to have been introduced by man.' Practically all 
of these introduced forms are found only in the coastal region, in 
the open lands and thickets, almost none of them being found in 
the forests. In contrast to these figures, Manila, with its vegeta- 
tive conditions entirely changed by the destruction of the original 
vegetation, presents a total of 1,007 species, including the culti- 
vated plants, of which 457 have presumably been introduced by 
man, either purposely or accidentally. The percentage of 
endemism for the Lamao flora is about 40, the general average 
for that of the Archipelago as a whole, while for Manila it is only 
about 12. If we exclude 36 endemic species which are included 
in the "Flora of Manila," but which are not true natives of the 
area covered, then the endemism for Manila is only about 8.7 per 
cent. 
Much has been published on the origin of cultivated species, 
and the subject has been admirably summarized by A. DeCandolIe 
in his work on the "Origin of Cultivated Plants." While this 
* Merrill, E. D. The Flora of the Lamao Forest Reserve 
1 (1906) Suppl. 1-141. 
' The original estimate was fifty-four, Merrill I c. 9. 
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This Journal 
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