in the field the necessary attention was paid to oecological factors. 

 It was never carefully examined and noted in what kind of habitat 

 each species lived and how it behaved there, neither in which num- 

 bers it occurred. The superterranean and subterranean development 

 of the plants, the degree of weathering, the texture, structure, wa- 

 tercapacity and microflora of the soil, the temperature, the intensity 

 of light, the mutual relations between flora and fauna, were never 

 yet seriously investigated. Many of the scientific sides of the pro- 

 blem were insufficiently attended to or entirely neglected and the 

 consequences of this neglect did not fail to appear. 



It is only fair to admit that in 1886, when the eminent savant 

 Treub, who was no florist and whose knowledge of tropical plants 

 was very limited, made his ever-memorable trip, the Buitenzorg Her- 

 barium was in a sad state. The collections were very incomplete, 

 they were badly named and worse labelled; hence by studying them 

 nobody could obtain a sufficient knowledge of the Indian vegetation 

 and the factors determining it. Information dating from that time 

 about habitat or frequency of the different species is for the greater 

 part unreliable. The comparatively little material, then extant, had as 

 a rule, not been collected in the manner it should be done, it was 

 often in a bad state of preservation and wrongly named; data about 

 altitude above sea-level, character of the habitat and local frequency 

 were often entirely lacking. In later years the situation has grown 

 much better. An investigator provided with scientific insight, with a 

 sense for criticism, with sufficient knowledge and experience, and 

 not sparing labours can, at the present time, find in the Buitenzorg 

 collections many reliable data about habitat and local frequency of 

 a multitude of species, which data will allow him to draw conclusions 

 in the domain of oecology. Therefore one is quite justified to claim 

 from the recent publications on the new flora of Krakatao a more 

 exhaustive and especially a more critical elaboration of the subject 

 than might be reasonably expected from the former ones. 



Doubtless a very important part of the Krakatao-problem lies 

 in the answer to the question by which means the present flora, 

 which all authors agree to be new ''), has reached the island. It is 



1 ) When this paper was about to go to the press the following reference in Bota- 

 nisches Centralblatt, Neue Folge 11 (Band 153) 1927, p. 155 came to my notice: 

 Scharff, R. F., Sur le pr obi erne de I' ile de Krakatau. C. R. Congr. Ass. 

 franc. Grenoble (Biogeogr-) 1925 4 S- Nach kurzer Schilderung der Eruptionen und 

 ihrer Wirkung iiuszert Verf. seine Zweifel daran, dasz Pflanzen- und Tierleben 1883 

 vollstandig vernichtet worden sind. also die heutige Lebewelt der Insel insgesamt 

 durch passive Verbreitung nach dort gelangt sei. Fur eine ganze Reihe von subterranen 

 und Felsspalten bewohnende Formen weist er die Moglichkeit des Uberlebens einer 



