282 



forest which will eventually develop into the complex old wild-forest. The 

 main object of further investigation must be to record these alterations in 

 the plant formations and their competetive struggle, as far as possible at 

 regular intervals. 



One is at some pains to ascertain what may be the meaning of 

 the above statement, which is far from lucid. I pointed out already 

 that, with the exception perhaps of the littoral flora, we do not know of 

 a single plant how it has come to Krakatao, if it might have come 

 after the eruption. We do not know with certainty whether animals 

 and wind have played <.iny part in carrying seeds to Krakatao, much 

 less whether they have played an important part; one can only 

 guess. The assertion that the vegetation on Krakatao is anything but 

 normal, is quite enigmatical: perhaps Mr. Docters van Leeuwen 

 confounds here normal with stable. As a matter of fact it is quite 

 normal that a comparatively young secondary vegetation in the 

 tropics is very unstable: new species constantly appearing and many 

 old species diminishing in number or disappearing altogether. It is 

 not clear why Mr. Docters van Leeuwen asserts that in 1922 

 several plant associations had already been formed. From the very 

 first such associations have been developing. Treub found them 

 already in 1886, within 3 years after the eruption. In almost every 

 unstable vegetation associations may be observed. Even in localities 

 where in severe east-monsoons the weeds are almost entirely des- 

 troyed by the prolonged drought, the sand-dunes of Madura 1) for 

 instance, they form in the next west-monsoon new and typical 

 associations, which develop whithin a few months. The more so the 

 plants on Krakatao, which all the year round find favorable conditions 

 for their undisturbed development. Why the vegetation of Cyrtandra 

 su/cata is called unnatural is not clear, as it has not been planted 

 by man but was formed by natural causes. Perhaps Mr. Docters 

 van Leeuwen means uncommon. He mentions as a curiosity that 

 in the three years during which ,,he has taken stock of the island" 

 the vegetation has noticeably changed. But every undisturbed young 

 secondary vegetation in the tropics rapidly changes. 



As Penzig examined only the beach at Zwarte Hoek and 

 some slopes on the north-western side, it is not at all proven that 

 at the time of his visit tall grasses ,,nearly clothed the whole of the 

 ,,island". In the short time Penzig stayed on Krakatao he could 

 not possibly have investigated more than a very small part of it 

 (See p. 88). 



*) See p 72, footnote 1. 



