Floristic Interchanges Between Formosa and the Philippines

THE FLORAS of Formosa and the Philippines are, in spite of the ir geographic proximity , distinctive in their general nature. The tw<? regions wereseparated by the Formosan rift (the Bashi Channel), probably in the early Tertiary, long' before their connections with other respective neighboring areas were severed. Thus the bulk of the Formosan flora was derived from China or from other floras that spread to Formosa through the Chinese mainland, while the bulk of the Philippine flora was derived from Mal aysia and other lands south of the Asiatic continent. The distinctiveness of the two floras has been amply demonstrated by Merrill (1923). It will suffice to mention here the many tropical and southern families that are present in the Philippines but absent from Formosa, such as the Dipterocarpaceae, Centrolepidaceae, Monimiaceae, Nepenthaceae, Cunoniaceae, Erythroxylaceae, Dichapetalaceae, Datiscaceae, Clethraceae , Epacridaceae , and Salvadoraceae. On the other hand, many other families, clearly of northern origin, occur in Formosa but are entirely absent from the ' Philippines, such as Cephalotaxaceae, Taxodiaceae, Cupressaceae, Betulaceae, Lardizabalaceae, Trochodendraceae, Papaveraceae, Geraniaceae , Callitrichaceae, Pyrolaceae, .Diapensiaceae , Valerianaceae, and Dipsaceae.