231 



come a source of food for the new vegetation. (See also p. 85). 

 There is not a single indication that this new vegetation developed 

 earlier on the shore than in the interior, hence it will be difficult 

 to prove that the littoral vegetation more than any other one 

 ^contributed to enable other plants to start living a few years later, 

 ,,a little more in the interior". Unless and this is a most alluring 

 hypothesis - it did so from a distance by some hitherto unknown 

 kind of emanation. 



The mistake made by Mr. Docters van Leeuwen in con- 

 sidering all ferns found by 1 reub as plants content with dry soils, 

 was already discussed on p. 221. Such another mistake is made by 

 him where he says that Saccharum spontaneurn L., Spathog/ottis 

 plicata Bl. and Arundina speciosa Bl. are plants of dry soils. As a 

 matter of fact these plants, especially the first, require rather much 

 moisture to prosper (See pp. 100 seq.). On p. 221 I already pointed 

 out that Mr. Docters van Leeuwen takes here into regard 

 only the dry surface of the soil seen by him, not the moist deeper 

 layers. As to the large number of beach-plants living in symbiosis 

 with fungi, Mr. Docters van Leeuwen has apparently not 

 well understood the statement of Dr. Von Faber who did not speak 

 of beach-plants but of plants of coral-islands '), which is quite 

 another thing. In the leached-out interior of the older coral-islands a 

 lot of non-littoral species live. Dr. Von Faber kindly informed me 

 that such beach-plants as are halophytes do not possess mycorrhizae. 

 Among the others which grow on a non-saline soil there are some 

 which have mycorrhizae, others which live in symbiosis with bac- 

 teria. Considering that Leguminosae on Krakatao up to 1919 have 

 been found only on the beach and the localities immediately behind 

 it (See p. 170), it is difficult to conceive how these plants could 

 help ,,energetical/y" in rendering the soil fertile. In his list of ,, forest- 

 plants" (Appendix 111) Mr. Docters van Leeuwen does not record a 

 single Leguminosa. 



It is quite true that many plants could not live on Krakatao 

 before there were humid forests. Such forests, or at least groves, 

 may in the higher ravines have been present within comparatively 

 few years after the eruption. Treub when approaching Krakatao 

 saw as early as 1886 rather large plants growing near the top. The 

 plants requiring much shade and moisture which were found on 



l ) Handelinqen Eerste Nederlandsch Indisch Natuurwetenschappelijk Congres (1919), 

 p. 128. 



