144 



the strongly accidented locality and the dense 5acc/>arum-vegetation 

 presented so many obstacles, that notwithstanding our utmost exer- 

 tions, we were unable to effect our purpose *) in the short time we 

 could dispose of; we did not reach a greater height than at best 

 40 or 50 m., perhaps even less. Then we went back to the shore, 

 embarked again, rounded the eastern and the northern coast and 

 landed at Zwarte Hoek, where we investigated the same beach as 

 Treub had done in 1886, Penzig in 1897, Valeton in 1905. The 

 interior of the island above Zwarte Hoek, of which our predecessors 

 had likewise examined the flora, was not explored in 1906; only on 

 the very base of the basaltic rocks some plants were collected. 



The plants collected in 1906 are recorded beneath in 4 lists, of 

 which the first contains the finds made at Zwarte Hoek, the second 

 the vegetation of the beach on the south-eastern side, the third 

 the vegetation of the examined part of the interior on the south 

 eastern side, whilst the fourth contains some plants mentioned by 

 Ernst for this trip but not observed by me. I thought it advisable 

 not to follow the example given by former authors on Krakatao 

 who united all their finds into a single list without indicating the 

 habitats, because in this way it becomes impossible to compare the 

 vegetation of different localities. 



A. FINDS AT ZWARTE HOEK. 



The locality, described already on page 36, consists mainly of 

 a level beach extending from Zwarte Hoek in a south-eastern direct- 

 ion. This beach is + :i /4 km. long; it consists of sand, ashes and 

 pumice and bears on the land-side several big boulders. In 1897 it 

 was probably still narrow 2 ); if so, it has since that year increased 

 in size; in 1908 it was in its broadest part 150 m. 3 ) wide; in 

 1906 it can have been but little narrower. Only the younger parts of 

 this locality were in 1906 a beach in the oecological sense of the 

 word, their vegetation consisted mainly of halophytes; the older 

 parts, especially those close to the base of the rupture, were leached 

 out by the frequent rains and possibly also by ground-water moving 

 in a horizontal direction. From the fact that Saccharum spontaneum 



1) See Ernst, Neue Flora Vulkaninsel KraUatau (1907), p. 32-34. 



2) Cf. Penzig in Ann. |ard. Bot. Buitenzorg XVIII (1902), p. 97. Treub, who 

 visited the same locality in 1886, says nothing on the breadth of the beach in that year. 



3 ) According to the map in |aarverslag van den lopographischen Dienst in Neder- 

 landsch-lndie (Year-book of the Topographical Survey Service in the Dutch Indies) 

 1908, plate XXIII. 



