200 The Philippine Journal of Science i9u 
and smaller islands, the other from southwestern Mindanao 
through a long chain of fair-sized islands, of which Basilan, 
Jolo, and Tawi Tawi are the most important. Unfortunately the 
southwestern corner of the Archipelago is still almost unknown 
botanically ; but there is at present a strong balance of evidence 
to favor the view that somewhere or other there is a definite 
break between the floras of Borneo and of the Philippines as a 
whole. Statements have to be guarded, as so little is known of 
Borneo, but while the plants of the two regions are generally 
similar, there appears to be a very small percentage of specific 
identity. If the smaller islands near Borneo should prove to 
resemble it in their flora, and the trivial evidence at hand tends 
in that direction, it will merely prove that botanically they 
belong with the larger island, and that the political and botanical 
boundaries of the Philippines and Borneo are not the same. 
Whether or not this proves to be the case, it is thoroughly 
established that with regard to flowering plants, there is such 
a thing as a definite Philippine flora, containing an unusually 
high percentage of endemic species ; that its affinities are 
primarily Malayan ; moreover, that there is a strong Himalayan 
element, especially in northern Luzon, although some of the 
species so considered extend also to Malaya; that there is a 
small but very definite Australian element; and finally a most 
important Pacific alliance. All of these points, except the last, 
have been fully discussed in papers previously published . 2 
If any outside area can be indicated as more nearly similar 
botanically to the Philippines than is any other, the present 
evidence is strongly in favor of Celebes. In spite of this, it is 
certain that mere proximity is not the only factor, for whether 
the determining basis be the number of identical species or the 
general resemblance of the flora as a whole, the Philippines 
come closer to the Malay Peninsula and to Java than to Borneo 
or Annam, to Samoa than to Formosa. 
It might then be supposed that when botanical boundaries 
come to be drawn within the Philippines, the separate islands 
would be found to have quite distinctive floras. This is not 
2 See Rolfe, R. A. On the Flora of the Philippine Islands, and its prob- 
able Derivation. Journ. Linn. Soc. Bot. 21 (1886) 283-316; Merrill, E. D. 
New or Noteworthy Philippine Plants, V. Philip. Journ. Sci. 1 (1906) 
Suppl. 169-246; Merrill, E. D. The Malayan, Australian and Polynesian 
elements in the Philippine Flora. Ann. Jard. Bot. Buitenz. Suppl. 3 (1910) 
277-306; Copeland, E. B. The Comparative Ecology of San Ramon Poly- 
podiaceae. Philip. Journ. Sci. 2 (1907) Bot. 1-76; Copeland, E. B. The 
Ferns of Mount Apo. Leafl. Philip. Bot. 3 (1910) 791-851. 
