207 



forgotten that any person in a favorable locality in the tropics can 



collect a great number of species within a few hours. But in the 



case of Krakatao such a collection, not accompanied by reliable 

 oecological data, is of exceedingly little value. 



5. On April 25th an exploration-trip was made in the lower ravines for the purpose 

 of seeking a track to the top. First the way follows a water-course in the field 

 of Saccharum spontaneum L., swarming with thousands of ants. After that a 

 lovely spot was reached, the gully of a dry water-channel, with many tall 

 trees and a good deal of underwood and fern. Many trees there were belong- 

 ing to a few species, especially the F/cus-family, i.a.: /. Ficus flstulosa 

 Keinw., 2. F. fulva Reinw., 3. F. varieyata Bl. some of them quite big; fur- 

 thermore 4. Raderrnachera glandulosa Miq., 5. Homalanthus popu/nca O. A., 

 6. Macaranga tanarius M. A,, 7. /Vauc/ea purpurascens Korth., 8. Melochia 

 umbellata Stapf, 9. Trema orientate Kl. 10- I'ipturus incanus Wedd., 

 11. Villebrunt'd rubescens BL, some of the specimens so robust that one 

 would certainly have assigned an older age than 36 years to them, if one 

 had not known the history of the island. It was a peculiar kind of virgin forest 

 such as is rare in |ava, since it was made up by many individuals representing 

 but few species. Epiphytic ferns grew everywhere, a.o. good-sized Asp/enium 

 nidus L. I his also was remarkable, because Backer mentions that epiphytes 

 were still rare in 1908. The great variety of mushrooms and toadstools 

 vegetating on the fallen treeboles was very striking, the more so as Ernst 

 only mentions 2 of these. Mr. Docters van Leeuwen also found several 

 new species of ground-orchids, a. o. Habenaria spec., Eulophia macrostachya 

 Lindl., Nervilia aragoana Gaud. The species most abundant at the time of 

 former explorations, Arundina speciosa Bl. and Spathoglottis p/icata Bl. now 

 proved to have been ousted by the spreading forest. The zoologist collected 

 a number of lob- and lugworms (Lumbricus spec.) which had not been per- 

 ceived in 1908. At an altitude of about 100 m. the way was blocked by an 

 absolutely unscalable precipice. About 50 plants were collected at all. 



Mr. Docters van Leeuwen does not mention from which 

 point he tried to penetrate into the interior. In 1908 the investigators 

 (see Chapter VIII) started from the south-eastern angle. It is next 

 to impossible that Docters van Leeuwen in 1919 followed 

 quite the same route and examined the very same ravines as his 

 predecessors had done. The track made in 1908 must within a few 

 years have been entirely shut up by the dense tropical jungle and 

 could not possibly be rediscovered. Referring to what I have said on 

 p. 5 7 about the composition of comparatively young vegetations 

 in the tropics I need scarcely argue here that from a comparison of 

 the finds in 1906 or 1908 with those in 1919 no reliable conclusion 

 can be drawn about the appearance or disappearance of individual 

 species, though we are fully warranted to believe that - generally 

 speaking the young forest had extended still more and probably 

 considerably downwards. 



