23 



sula will certainly yield *a great many additions to its known 

 flora. The large island of Sumatra is practically unknown from 

 .a botanical standpoint, although extensive collections have 

 been made there in the past, and important contributions to a 

 knowledge of its flora have been published; exploration, how- 

 ever, has been intermittent and limited to certain small areas. 

 The flora of Celebes and of other, islands in the Archipelago 

 proper is no better known, while the explorations made in New 

 Guinea within the past twenty-five years, so far as the collec- 

 tions have been worked up, give us but a very imperfect 

 conception of the great richness of its flora. In the Philippines 

 great progress has been made in botanical exploration and 

 publication in the past sixteen years, and in that time the list of 

 known species has been more than trebled, yet with all that has 

 been accomplished in the Philippines in recent years, current 

 collections from previously unexplored regions invariably 

 present a high percentage of additions to the known flora, so 

 that it is improbable if we now actually know more than three- 

 fourths of the species that occur in the Archipelago. 



The flora of Malaya is an exceedingly rich one in families, 

 in genera, and in species, and the region presents an infinite 

 number of interesting problems from the standpoint of phyto- 

 ^eography. It is very probable that the entire Malayan flora 

 from the Malay Peninsula to the Philippines and New Guinea, 

 when fairly well known, will approximate 40,000 species of 

 plants in the higher groups alone, but it will be many years 

 before even an approximately complete list can be compiled 

 for enormous areas remain to be explored, and the collections 

 made must be critically studied and compared with material 

 from other parts of this vast area. While a certain number of 

 species are generally distributed throughout the entire extent 

 of Malaya, these are, in large part, the coastal forms, and those 

 found in the settled areas where the character of the original 

 vegetation has been profoundly altered by man and his agricul- 

 tural activities. In the virgin forest in practically every island, 

 at least in those islands of any considerable size, so far as our 

 present available data shows, there is always or nearly always 

 a high percentage of endemism; further in different parts of the 

 same island, depending on local climatic conditions and appa- 

 rently largely on the seasonal distribution of the rainfall 

 throughout the year, there is very frequently a marked local 

 endemism, the vegetation of one area presenting a high 

 percentage of species entirely different from those found in 

 another area often only a few miles distant. Even mountains 

 which are separated by plains or arms of the sea only a few 

 miles in width often differ markedly in their vegetation. Thus 

 in the Philippines Mounts Maquiling, Banajao, and Mariveles, 



