274 



This statement I think is not sufficiently warranted. In 

 Appendix II to his paper on the excursions of 1919 (See p. 

 234 seq.), Mr. Docters van Leeuwen records 58 Phanero- 

 gams as found on or near the beach of Krakatao to which 

 number should be added 5 species (See p. 247), that were 

 certainly found on or near the beach though they were not 

 recorded in Appendix II, hence in total 63 species. In Appendix III 

 he mentions 38 Phanerogams considered by him to be forest- 

 plants, hence found in the interior. Large as the difference 

 between the number of plants found on or near the shore and 

 that in the interior may be, we have no right to conclude 

 from it that the shore is richer in Phanerogamic species than 

 the interior. There is another conclusion which seems to me 

 far more correct. The beach, the sandy parts of it at least, 

 can be very comfortably investigated throughout a length of 

 more than 4 km. 1 ); most of the species growing on it are 

 herbaceous or shrubby and, being well exposed to the light, 

 flower freely, hence are apt to be collected. The interior offers 

 much more difficulties to the investigator and many species 

 there are either arboreous or, by cause of want of light, do 

 not flower in which case they are easily overlooked. Experience 

 teaches that unsufficiently trained collectors in the tropics 

 often neglect to gather materials from arboreous or non- 

 flowering species. Hence they easily get the impression that 

 a forest is much poorer in species than it really is. Moreover, but 

 a very small part of the innumerable ravines and ridges of 

 Krakatao can have been examined in 1919 and one often sees 

 that ravines and ridges but little remote from each other differ 

 in vegetation. By examining but a small part of the ravines and 

 ridges one gets but a part of the species present. In 1923, 4 

 years after the trips of 1919, Mr. Docters van Leeuwen 

 asserted 2 ) that a great many new plants, especially Fungi, 

 Musci, Hepaticae and Lichenes, had been noticed on Krakatao. 

 It is much less probable that these species had newly settled 

 there in those 4 years than that many plants present already 

 in 1919 were overlooked in that year. From the results publish- 

 ed it does not at all appear that the investigated lower slopes, 

 covered with a dense Saccharum-]ung\e intermixed with scattered 



') See p. 64, footnote 1. 



2 ) Ann. |ard. Bot. Buitenzorg XXXII (1923), p. 157. 



