12$ 



2. On all three islands of the Krakatao-group the beach bears mainly 



a pes-caprae-formation. Mangrove is entirely absent. Only on 

 Lang Eiland forest has begun to develop. More in the interior 

 the vegetation has the character of a savanna or a grass-steppe. 

 This vegetation consists partly of grasses of more than a man's 

 height which form a dense jungle in localities fit for them. On 

 the hills and the ridges less tall grasses, numerous ferns and 

 scattered Phanerogams are found. On the rock-sides, now like 10 

 years before, ferns greatly predominate. Shrubs are few in number, 

 trees are almost entirely absent. It will take a long time before 

 the higher layers of the soil are sufficiently weathered and possess 

 a sufficiently quantity of humus for bearing again a dense forest. 



3. Most of the Phanerogams were introduced by sea-currents, fewer 



by the wind, very few by animals. 



These conclusions cannot possibly be agreed with. Penzig in 1897 

 like Treub in 1886 investigated but a very small part of the island. 

 Nothing is known of the flora of the localities not investigated in those 

 years; hence from the fact that in 1897 species were found that were 

 not seen during the most incomplete investigation of 1886, may by no 

 means be deduced that these arrived after 1886. Consequently nothing 

 can be said with certainty about the increase of the number of species 

 between 1886 and 1897. For neither of these years the total number 

 then present can be even guessed at with some approach to accuracy. 



It is certain that in 1897 the beach at Zwarte Hoek bore a 

 greater number of species and a much denser vegetation than in 

 1886, but all littoral olants found there may have occurred in 1886 

 elsewhere on the beach of Krakatao. It is quite unknown when they 

 first reached the island. Whether plants of the interior had already 

 been introduced in 1897 and, if so, which plants, from where, when 

 and in which manner is utterly unknown. Littoral forest was in 1897 

 seen only on Lang Eiland but may quite well have been present on 

 non-investigated parts of the beach of Krakatao. By far the greater 

 part of the beach remained unexamined in that year, and this part 

 was not even visible from Zwarte Hoek. It is quite conceivable that 

 on Krakatao no mangrove-vegetation was found, for the coasts of 

 the island are unfit for such a vegetation. But some stray specimens 

 of species, as a rule growing in the mangrove, may have occurred 

 here and there on the beach '). 



Cf. p. 98, footnote 1. 



