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1 



FLORA OF TIIE PHILIPPINE ISLANDS. 305 



everywhere to be found throughout the group. During these up- 

 heavals, with accompanying subsidences in adjacent areas, it is 

 probable that the various islands were severed and reconnected 

 in different directions, not only with adjacent regions, but with 

 each other, and that the various plants and animals diffused 

 themselves about as circumstances permitted, the various con- 

 nections serving as stepping-stones from one island to another. 

 Possibly they were once more continuous ; but, on the other 

 hand, the island of Luzon was formerly cut into three, and there 

 is abundant evidence to prove that the southern portion was 

 long separated from the northern. Coral-reefs, too, abound in 

 various directions throughout the group, and afford certain 

 evidences of former submersion ; but it seems probable that 

 these subsidences were of a local nature rather than a recent 

 general subsidence, which must have destroyed a large portion 

 of its endemic vegetation. 



At the time when the land-connection with the Chinese region 

 permitted a partial migration northward, a certain commingling 

 of the two floras took place, some of the Chinese plants moving 

 southward. After a considerable period of stability this south- 

 ward migration was probably hastened by the cold of the early 

 Grlacial Period, during which the connections were being gradually 

 severed, some of the species reaching Formosa, some the northern 

 part of Luzon, and others getting still further southward. The 

 connections to the southward were also being severed ; and 

 thus the various plants and animals became isolated, some of 

 them with a w ide dispersion within the group, and others with 

 a considerably restricted range. A period of comparative sta- 

 bility at length set in, which has continued down to the present 

 time; and during this period of long isolation the species have 

 become modified into distinct local species, some of them having 

 a very restricted range within the group. And, lastly, since the 

 period when the connections with surrounding countries were cut 

 off, a number of additional plants have reached the islands — by 

 marine currents and other causes known to effect the dispersion 

 of plants, and by man's agency — some of which are so thoroughly 

 established or so widely diffused as to appear truly indigenous. 



Mr. Wallace, in 1876 ('Geographical Distribution of Animals,' 

 vol. i. p. 344), speaking of the Philippines, remarked : — " They 

 are, in fact, truly insular, while the other [Malay] islands are 

 really continental in all the essential features of their natural 



