158 
In the second appendix have been catalogued in two parallel 
columns the plants of the Krakatau islands and those of Sebesy, 
so as to afford a ready survey of the two floras, and make a 
comparison possible. The Krakatau list contains all the plants 
thus far collected there by myself, so that this list also gives 
a complete picture of all the plants found up to date. I avail 
myself of the opportunity of getting this list also printed, 
because I intend to watch the Krakatau-flora for a number of 
years more before proceeding to a definitive elaboration of my 
notes relating to the flora of Krakatau. On the problem as to 
how the plants came to Krakatau the light has been shed that 
was still possible. It is now no longer possible to form anything 
more than an opinion on the spread of most of the plants. 
The three factors, sea-currents, winds and animals (including 
man) are known to have each of them played an important 
part, and we shall have to leave it at that. But the vegetation 
is as yet anything but normal, though several plant-associations 
have already been formed, but these are in most cases still 
very poor in the number of different species; others like the 
vegetation of Cyrtandra sulcata Bl. which largely covers Mount 
Rakata from about 300 Meter to the top, are very unnatural, 
so much so that even in the three years in the course of which 
I have taken stock of the island, changes have been distinctly 
noticeable which point to this vegetation being only of a 
temporary character; in the same way as the savanna vegetation 
of tall grasses, which clothed nearly the whole of the island at 
the time of Prnzie’s visit as it still does large areas now, has 
had to yield place to the mixed forest which will eventually 
develop into the complex old wild-forest. Similarly on Verlaten 
Eiland the great forest of Casuarina equisetifolia Forst. is in 
course of being replaced by a mixed forest. The main object. of 
further investigation must be to record these alterations in the 
plant formations and their competitive struggle, as far as possi- 
ble at regular intervals. 
Also on Sebesy-island a number of plantformations have been 
built up, partly the same and partly different ones from those 
at Krakatau. The number of different plants also is far greater: 
