284 



f. A forest of big heavy species of trees does not exist on Krakatao; big 



li.uiir. are also missing. 



g. the epiphyte flora is far richer on Krakatao than on Sebesy, not only that 



of higher plants such as orchids and ferns, but also of mosses. 



h. Ficus varicgata only occurs sporadically on KraUatao and of smaller dimens- 

 ions than on Sebesy. 



On this paragraph I can be very brief. 



a. By littoral vegetation Mr. Docters van Leeuwen obviously 



understands only the Pes ceprcfe-formation. It is to be 

 regretted that he does not mention the species of which 

 it is ,,so very rich " Now his assertion is without value. 

 For his list of littoral plants given in the Transactions of the 

 Congress (1920) 1 refer to p. 234. 



b. In 1908 the B<3/T//jyto/?/'c?-formation on Krakatao was frequently 



lying immediately behind the floodmark (and not behind the 

 first zone of plants), wherever the beach was being washed 

 away by the waves. There is no reason to suppose that in 

 1919 and later years it should have been otherwise. 



c. We are not told how far the Jittle forests dotted on top of 



,,the old ash-layer" were distant from the sea. It is a long- 

 known fact needing no new proof that the light winged seeds 

 of Casuarina equisetifolia and other tall trees may be carried 

 over some distance by wind. It was f.i. already mentioned 

 by Kamerling 1 ) in 1911. See also p. 91, No. 6. 



d. Krakatao possessing neither muddy shores nor coral-terraces 



running dry or almost so during the ebb-tide, there is no fit 

 substratum for mangrove-plants to develop upon. 



e. For the ,,very young" forest in the ravines, see Chapter IX in 



which the excursion of 1908 is discussed. From the fact 

 that seeds of Macaranya tanarius taken from the intestines 

 of a shot bird had retained their germinative power it may 

 certainly not be deduced that the seeds leave the digestive 

 canal of living birds likewise in an undamaged state. Even if 

 this might be the case one may only conclude that the birds 

 can take an active part in spreading the tree over the is/and 

 but not that they have introcuced the plant from elsewhere. 



') Dr. 2. Kamerling, Over liet voorkomen van Wortelknolleties bij Casua/v'na 

 in Nat. I ijdschr. Ned. -Indie LXXI (151 1), p. 20. 



