206 



arinas. Ipomoea long/flora is much more robust but I never saw it 

 at a height of at least 20 meters form the dense carpet requisite for 

 entirely covering a tall tree. Columella trifolia, on the contrary, as 

 Ernst 1 ) already rightly mentioned, can reach a great height and 

 form there a dense canopy. 



It is much to be regretted that Mr. Docters van Leeuwen 

 does not mention a single one of the ,,various bushes and plenty of 

 ,,trailing and creeping plants" which formed a thick undergrowth of 

 the Casua/-//?a-forest. Of the ,,usual plants" of which the Pes caprae- 

 formation was composed he mentions only six; it is not clear why 

 the other ones need not be enumerated in a paper intending to sketch 

 the development of the flora. It would surely be of interest to know 

 whether the Pes caprae-formation on this side of the island had 

 grown much richer in species since the visit of Ernst. Appendix I, 

 giving all the plants found in 1919 on Krakatao, cannot help us 

 here. It is remarkable that whilst in 4 Ca/?ava//a is given as one 

 of the plants with which the shore was overgrown, this species is 

 not mentioned for this trip in Appendix I, giving all the plants 

 collected on Krakatao. Of the components of the Birringtonia-for- 

 mation but 3 are recorded and these only in a general way; many 

 typical and conspicuous trees and shrubs of this formation '-) which 

 Ernst and his companions had found on this side of Krakatao 

 in 1906 (see the list on p. 153 seq.) are not mentioned. It is true 

 that in Appendix 1 to Mr. Docters van Leeuwen's paper 

 most of these species are recorded as found on Krakatao in 1919 

 but this appendix gives no information on which side of the island 

 and in what numbers they occurred, so that it is impossible to 

 compare the littoral vegetation of 1906 with that of 1919. 



The belt of grasses lying behind the Casuarinas (in 1919 never 

 immediately behind the beach or behind the Barringtonia-asso- 

 ciation? see 15) consisted of various species of which Saccharum 

 spontaneum L. was ,,most in evidence". We are not told whether 

 this belt was everywhere dense, neither which other plants than 

 Saccharum occurred in it. It is apparently deemed of more importance 

 for science to tell that about 100 species were found, labelled 

 and dried, than to mention which these species were and in what 

 habitat and in which numbers they occurred. It should never be 



!) Ernst, Neue Flora Vulkaninsel Krakatau (1907), p. 30. 



-) i.a. Calopliy/lum inophyllum L., Desmodium umbellatum D.C.,- Doc/o/iaea 

 v/scosa /ace;., Erythrina var/egrafa L. var. orientalis Merr., Guettarda spec/osa L., 

 Hernandia peltata Meissn,, Morinda citrifolia L., Pandanus tectorius Sol., Ponga- 

 mia pinnata Merr., Scaevola frutescens Krause, Sophora tomentosa L.. 



