Endemic Floras

Abstract

THE old problem of endemic species is continually being investigated by naturalists, either from the old or from new points of view. A number of papers recently issued refer to various aspects of the problem or provide additional material for its consideration. Thus, for example, the value of Wallace's and Weber's lines in the Malay Archipelago is discussed by Merrill (“Distribution of the Diptero-carpaceae,” Philippine Journ. of Science, vol. 23, pp. 1-33, 1923) on the evidence offered by the Diptero-carpous trees. These are dominant in great areas of the primary forests of Malaysia, particularly of Borneo and the Sunda Islands; they do not occur on open or cleared country, and their fruits cannot be widely dispersed by either wind or water. Their distribution should therefore give evidence as to where land connexions have existed. Merrill points out that the evidence both from this and from geological sources supports the assumption that the Philippines, Celebes, and the eastern Sunda Islands have for long been subject to archipelagic conditions. On the contrary, western Malaysia and the New Guinea regions have belonged respectively to the Asiatic and Australian continents. Wallace's line is therefore modified to cut off Borneo and Palawan from the Philippines, and thus to form the western boundary of the unstable area, the eastern limit of which is defined by Weber's line.