96 



investigation in 1886 was carried on with sufficient accuracy, we 

 arrive at the conclusion that in the 1 1 years elapsed between the 

 two excursions 12 new littoral plants (No. 1, 2, 3, 4, 5, 6, 7, 8, 9, 

 10, 11, 12, 13 and 16 of the above list), moreover Saccharum, had 

 established themselves ;'/; the locality invest/gated and several of 

 these species (I, 2, 3, 8, 9, 10 and Saccharum) occurred in numerous 

 specimens. All these new littoral plants (Saccharum is no littoral plant) 

 have seeds or fruits fit to be carried along by sea-currents; of 3 of 

 these species (No. 1, 12 and 13) Treub had in 1 886 already found 

 the seeds or fruits washed ashore. 



This, of course, by no means proves, nor even renders it probable, 

 that these new species had readied Krakatao after 1886. Treub 

 examined in 1886 only a small part of the beach, at best one sixth of 

 the whole '). As to the flora of the rest of the beach in that year \ve 

 are in complete ignorance. All the littoral plants found in 1897 at 

 Zwarte Hoek may quite well have grown in or before 1886 elsewhere 

 on the beach of Krakatao -). Seeds or fruits of littoral species are 

 often carried along for some distance by a current running parallel to 

 the beach and then washed ashore. One specimen may circumstances 

 being favorable in this way spread its posterity far over the strand. 

 I need scarcely argue that if only part of a beach of an island is 

 investigated and one might find there seeds, fruits or young seedlings but 

 no' large plants, this by no means furnishes proof that the species in 

 question has but recently reached the island or has newly established 

 itself. In order to decide on this point one has to examine thoroughly 

 the entire beach. Such an investigation, which would take very much 

 time, has never yet been carried out on Krakatao. Therefore it is 

 impossible to ascertain at which time the littoral plants found there 

 have first established themselves. This part of the problem will for 

 ever remain unsolved. 



Besides plants on the beach P e n z i g an his companions found 

 in the drift-zone at Zwarte Hoek 22 seeds and fruits 3 ) mentioned 

 by him under a specific name, viz. (recorded under the present names 

 arranged in alphabetic order): Barringtonia asiatica Kurz ( = B. speciosa 

 Forst), ~ Blumeodendon tokbrai Bl. ( Elateriospermum tokbrai Bl.), 



') See page 71, footnote 1. 



2 ) The statement of_P e n z \ q [Ann. |ard. Bot. Buitenzorg XVIII (1902), p. 97] that 

 ,,an fast alien anderen Seiten des KraUatau die felsige Kiiste steil und ganz unzugung- 

 ,,lich ins Meer ahstiirzt", does not hold qood for the east- and south-eastern side of 

 the island where a well-developed beach is present, the flora of which was first 

 examined in 1005 and more intensively in 1900. 



3 ) I have not been able to find these seed and fruits in the Buitenzorg collections. 

 Hence it is impossible to control the determinations, however desirable this would be. 



