44 



6. Calophyllum inophyllum L. (3 specimens). 



A very common tree of sandy beaches. It reproduces itself only 

 by fruits ') which possess floating power and are very often found 

 washed ashore. The beaches of Krakatao are very favourable to 

 this tree, which was found there at several excursions. 



As far as the identity of the fruits and seeds, found by Freub 

 on the shore of Krakatao, is established they belong to such trees 

 as are frequent on the beaches of the Dutch East Indies. Though, 

 as a rule, seeds found washed ashore on an island may quite as well 

 originate from that island itself as from any other one, we have to 

 admit in the present case introduction from elsewhere, as it was 

 impossible that within 3 years after the eruption fruiting specimens 

 of the trees in question could have grown on Krakatao. 



But from the fact that these fruits and seeds had reached the shore, 

 even when assuming that they had retained their germinative power, 

 may by no means be inferred, that the species they belonged to had 

 succeeded in establishing themselves on Krakatao. In order to grow up 

 to adult plants the seeds must come to a rest and therefore reach the 

 locality behind the flood-mark, which, circumstances being favourable, 

 in the case of small seeds may be effected by the waves and by the 

 wind but in the case of big ones only by a very high flood or a high 

 wave and occasionally perhaps by animals. When the tide runs low, 

 seeds are often left lying in and before the flood-mark, but when shortly 

 afterwards the tide is high, these seeds for a great part may become 

 floating again. \Vhere the beach rapidly decreases and therefore 

 forms a steep slope towards the sea, by far the greater part of the 

 seeds do not reach a safe locality behind the flood-mark; they remain 

 at the foot of the steep declivity and, when the tide is high, are in 

 continual movement so that they cannot germinate or, at least, not 

 root and grow -); all these seeds perish. The few seeds carried on 

 such beaches behind the floodmark by the aid of a high wave, may 

 germinate, but the young plants are far from safe as not only every 

 next high wave may damage or kill them but also the coastal line 

 is shifting backwards and the habitat, "in course of time, is destroyed. 



The best chance to live have fast growing plants possessing 

 long creeping stems, rhizomes or stolons by which they can soon 

 get away from their unsafe first habitat. Sometimes a beach increases 



') Described by Schimper, Indo-Malayische Strandflora (1801), p . 175 and 184, 

 tab. VII, fig. (I. Guppy found them in the drift-zone on tlie Keeling Islands. 



-) Cf. also K u in t- r I i n y in Natuurk. Tijdschr. Ned. Indie LXXXI (1921). p. 22 seq. 



