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it is most improbable that the ravines examined in 1919 were the 

 same as those of 1908. Unhappily Mr. Docters van Leeuwen 

 does not tell which plants he found beneath 400 m. and where and 

 in what numbers he found them, so that his remark is of little value 

 for future investigations. The few data contained in Appendix HI to 

 his paper are altogether unsufficient. As nothing is known of the 

 flora of the ravines above 400 m. in 1908 and Mr. Docters van 

 Leeuwen gives but very scanty and unsatisfying details of the 

 vegetation observed by him in the higher parts of the mountain, it is 

 not only quite impossible to compare the flora of 1919 with that 

 of former years, but in later years it will be very difficult to draw 

 reliable conclusions about changes in the vegetation after 1919. 

 Nothing is known with certainty. 



The flora of the beach is indeed, as a rule, the best explored, not 

 because one has to traverse it at every visit, which in most places 

 is a work of a few seconds or at best a few minutes, but because, 

 when the tide is low, the hcach itself forms a quite convenient and 

 inviting rode/ for the exploration of this narrow belt of the vegetation. 

 Nevertheless rare or inconspicuous species may be quite well over- 

 looked on the south-eastern and eastern beaches of Krakatao which 

 have a length of about 3 :i /4 km. and are densely clothed with trees, 

 shrubs and herbs. A really scrupulous investigation would require se- 

 veral weeks. Mr. Docters van Leeuwen asserts that 7 (the number 

 given in the Dutch text is 10) new genuine littoral plants have made 

 their appearance since 1908. He does not give the names of these 

 but on consulting Appendix I, one finds mentioned 8 beach-plants 

 and halophytes not yet recorded for former excursions, which of 

 course by no means proves that they were not yet present then, 

 the beach having been never yet thoroughly investigated. Only one 

 of these, Mucuna gigantea D.C. '), was found on Krakatao. This is a 

 rather large climber not rarely met with in the Barringtonia-iormation. 

 The seven other species were found on Lang Eiland and Verlaten 

 Eiland. Only two of them (Monerma repens P. B, and Thuarea 

 involute R. Br.) are genuine beach-plants; Halophila ova/is Hook., a 

 marine species, inhabits, as a rule such coral terraces adjacent to 

 the beach as run dry or almost so, when the tide runs low but are 



') The English text wrongly mentions this species, as found by Erns.t.qn Ver- 

 Idten Eiland. Ernst quite rightly recorded his plant under the name of Mucuna 

 pruriens D.C. In the Dutch text the specimen of Krakatao (1919) is mentioned as 

 M. pruriens D. C. The carelessness wherewith Mr. Docters van Leeuwen has 

 written his paper, the many discrepancies between the English and the Dutch texts, 

 make it a desperate task to search out anything reliable and valuable in it. 



