26 



5,000 feet, is covered with what may be called a well worked 

 secondary forest;" and again: "Certainly the 'untrodden 

 jungle ' of fiction seems to be as non-existent in this country 

 .as the ' rain forest ' of science." 



The swamp forests differ radically from the hill forests in 

 their constituent species, while on the mountains there is a 

 very radical change in the nature of the forest and in its 

 ■constituent species at an average altitude of from 2,500 to 3,000 

 feet. Naturally under these complex conditions botanical explo- 

 ration is by no means an easy task and thoroughly to explore 

 any given area involves intensive field work not only in all 

 months of the year, as only a part of the numerous species can 

 be found in flower or in fruit at any one time; but in order to 

 insure the collection of most of the species in a given area, 

 tlie work must be continued over a period of several years. 

 While some species are abundant, others are rare, and in certain 

 groups, notably the Bamhuseae and Dipterocarpaceae many 

 species produce flowers only at intervals of several years. 



Botanical exploration of these exceedingly complex forests 

 -is made more difficult by the great size of the trees; their 

 usually inconspicuous flowers; and the great difficulties 

 encountered in determining what tree is in flower or in fruit 

 from the fallen parts observed on the ground. Frequently the 

 only possible expedient to follow is to fell the suspected tree, 

 which is usually by no means an easy task, and very often when 

 the trunk is cut the tree will not fall on account of the support 

 given by its neighbours and the tangle of lianes uniting its 

 top with those of other trees. Similarly it is equally difficult to 

 •detect flowers or fruits on the large lianes which clamber to the 

 tops of the higher trees, and it is practically impossible to 

 locate flowering or fruiting specimens of the smaller and often 

 numerous epiphytes. 



From the standpoint of phytogeography it is perhaps to be 

 regretted that in the past fifty years so much attention has been 

 •devoted to the botanical exploration of such an island as Java, 

 the flora of which is comparatively well known, and so little 

 attention given to the immensely larger areas in Malaya which 

 rare practically terra incognita from a botanical standpoint, such 

 as most of the great Island of Sumatra, most parts of Borneo, 

 Celebes, Sumbawa, Flores, Timor. Ceram, Gilolo, New Guinea, 

 and numerous smaller islands. The continued exploration of 

 Java will doubtless add a fairly large number of species to its 

 known flora, but the return to be expected from field work in 

 Java, compared with what must»follow intensive field work in 

 any previously unexplored area in the islands mentioned iibove, 

 -can but prove insignificant. Up to the close of the last century 



