DR. O, STAPF ON THE FLORA OF MOUNT KINABALU, 111 
in class C, P being mainly due to the increase of coniospermous Melastomace:e, of species 
of Rhododendron and of Orchidez towards the upper limit of the second zone. It 
differs, however, extremely, so far as the last three columns are concerned. They show 
not only, as I have already pointed out, that the flora of the secondary forest is much 
more universal and that of the primary forest more individualized, even in the lower 
zone (see p. 91), but also that the increase of the endemie element takes place mainly 
among those plants which are apparently best fitted for dispersion. This difference 
still increases if we take the third or the fourth zone into consideration. I believe this 
phenomenon is not difficult to explain. ; 
The land at the foot of the mountain is of comparatively recent formation. It has 
been subjected to the process of clearing to a very great extent and probably for a very 
long time. It shares these peculiarities, and at the same time the general and physical 
conditions of plant-life, with the greater portion of Borneo and with many parts of the 
Archipelago. This process of clearing must have shaken the balance of the aboriginal 
vegetation, weakening it by the alteration of the conditions of plant-life, and at the same 
time opening the way for new competition. The invasion of this new element was, no 
doubt, favoured by the circumstance that the birds and mammals which might be the 
active means of plant-dispersion in this part of the country are commonly species of 
wider distribution, and many of them range freely Wind must have been also 
more effieient—as a spreading agency—on the cleared land than on the forest-clad 
highland, and finally man himself certainly often became voluntarily or inadvertently 
the cause of dispersion. All this is very different from what we find in the primary 
forest, as we ascend the mountain. Here the land is geologically old land. We have 
no evidence that its vegetation was ever disturbed to any great extent by clearings. 
The physical conditions of plant-life have no longer the same more universal character as 
in the hill zone; they deviate decidedly and become gradually more peculiar. The vege- 
tative aspect as well as the systematie composition of the primary forest, both the 
result of a long struggle under these very conditions, assume a similarly individualized 
character. The forest forms a harmonious union of congenial elements. Each of them 
is adapted in its way to the nature of the climate and of the soil, and all are in a state 
of comparative equilibrium which will not cease or materially change so long as the 
conditions out of which it has grown continue to exist. The animal kingdom undergoes 
- a similar change as the elevation increases, the endemic species becoming proportionally 
more numerous. Whitehead mentions migratory birds from the coast region of North 
Borneo as well as of Palawan, but not from the highland. "True, some birds were found 
there which are exactly identical with species known from the Himalaya, but they are 
not migratory. The fact remains, so far as I can see, that most of the mammals and 
birds of the higher zones—if not all—are confined to the highland, and never leave it. 
Wind may exercise its full power on the ridges, but not in the high forest which clothes 
the slopes and the bottoms of the valleys, and it can hardly at all affect the ground vege- 
tation, which comprises most of the coniospermous Melastomacez, Begoniacez, and a part 
of Orchidese. It might carry the extremely light seeds of Rhododendron or Nepenthes, 
which grow mainly on the ridges, a great distance. In any case, it has not been very 
Q2 
