33 



accounted for if we are to believe that all of these 3 islands had 

 to receive a new vegetation from across the sea. Why should the 

 introduction of plants on the lower parts of Krakatao have taken place 

 so much earlier than on the other two islands, which lie quite near, 

 rise to a height of upwards of 100 m. and receive, as appears from 

 their present vegetation, a sufficient amount of rain during the east- 

 monsoon. But if we admit the possibility that on Krakatao part of the 

 old vegetation has survived the eruption, it becomes quite conceivable 

 that on this is/and the flora was developed much further. The results 

 of the investigation of Lang Eiland by Boerlage in 1896 point into 

 the same direction. Whilst Treub 3 years after the eruption found 1 I 

 ferns on the lower parts of Krakatao, Boerlage, 13 years after the 

 eruption, found on Lang Eiland which he ascended to the top (147 m.i 

 but 4 fern-species '). This difference seems to me too great to be 

 quite accidental. 



From the above it is clear that I decidedly refuse to accept 

 Treub's argumentation that it appears from the composition of the 

 flora of Krakatao in 1886 that it cannot have originated from the 

 former vegetation. On the contrary, there are several indications 

 that the new flora of Krakatao partly originated or, at least, may 

 have originated from rests of the former one. 



For the conclusive force of Treub's argumentation that man 

 cannot have played any part in the introduction of the new flora 1 

 refer to p. 10 where I already have discussed this point. I think it 

 quite possible, even probable, that man did play a part. 



Against the argumentation advanced by Treub (cited by me 

 on pp. 18, 19) I oppose the following conclusions: 



/. It is entirely unproven and even improbable that the old 

 vegetation of Krakatao was totally destroyed by the eruption of J883. 



2. Hence a considerable part of the present flora may be the 

 offspring of rests of the old one. 



3. Man may quite well have contributed to the origin of part of 

 the present flora. 



The first and second of these conclusions are perhaps not 

 applicable to the other two islands of the Krakatao-group, Lang 





1 ) Viz. Ceropteris ca/ome/anos Und., Dryopteris unita Qfe>f., Ncp/irolepis exaltata 

 Schott,-Pteris vittata L 



