x,¢3 Merrill: Botanical Exploration of the Philippines 163 
have been sent to botanical institutions and botanists in Europe, 
America, Asia, and Australia. Most of our extra-Philippine 
material has been received in exchange for duplicates of Philip- 
pine plants. 
At the present time botanical exploration of the Archipelago 
has progressed sufficiently to enable us to distinguish between 
those areas presenting little of botanical interest and those 
of special botanical interest. In general, little of special in- 
terest is to be expected in the costal vegetation, in the settled 
areas and in the open grass country at low and medium alti- 
tudes, and in the second-growth forest. All regions at high 
altitudes, except a very few well-explored mountains, no matter 
what the type of vegetation, and likewise most regions at me- 
dium altitudes will be found to present much of special interest, 
while virgin forest, no matter what its location, will always 
be found to yield a high percentage of novelties. 
Whitford ‘ has estimated that approximately one-third of the 
total land area of the Philippines is now covered with virgin 
forest, one-sixth by second-growth forest, 40 per cent is grass- 
land, and 10 per cent is cultivated land. He has argued that 
all types of vegetation found in the Philippines to-day, outside 
of the virgin forest, owe their character to the presence of man, 
and I have considered more at length and tried to confirm this 
same proposition.® If our contention be correct, then two-thirds 
of the total land area of the Philippines to-day presents types 
of vegetation directly or indirectly influenced by the presence of 
man. The botanical distribution of the characteristic species of 
the various types of vegetation bears out the theory or conten- 
tion. Two-thirds of the land area of the Philippines, namely, 
the settled areas, the open grassland, and the second-growth 
forests, have a flora remarkable for the high percentage of widely 
distributed species, and equally remarkable for the low percent- 
age of endemic species. On the other hand, the virgin forest 
presents a very high percentage of endemism and a low percent- 
age of species extending outside of the Archipelago. The in- 
ference is that most of the species in the settled areas have been 
purposely, accidentally, or some undoubtedly naturally introduced 
into the Philippines within very recent times—that is, since the 
advent of man in the Archipelago—and that the virgin forest 
represents the original vegetation of the Archipelago as un- 
altered by the presence of man. The virgin forest invariably 
‘Bull. Forest. Bureau (Philip.) 10* (1911) 12. 
*This Journal 7 (1912) Bot. 145-208. 
