89 



paid little or no attention to oecological and biological relations 1); 

 in short, this trip may not be called a scientific oecological investig- 

 ation made by experts, but was a mere excursion of persons 

 interested into the problem but not seriously trying so solve it. 

 Necessarily the scientific results were few. The very short descript- 

 ions of the vegetation found in P e n z i g's paper give but scanty 

 and incomplete data about habitat and frequency of a small part of 

 the species collected; several of these are passed over in silence; 

 often it is not even mentioned whether a plant was found on the 

 beach or in the interior. P e n z i g, however, was fully aware of the 

 shortcomings of his investigations; he admits that the fact of a 

 species not having been found by him or his companions is by no 

 means to be considered proof that it did not occur then on the island. 

 The locality explored -) was about the same as that visited by 

 Treub 11 years before (see p. 36). The rest of the island, including 

 the so important ravines on the east- and south-east side, was not 

 visited. As might be expected the investigators first explored the 

 vegetation of their landing-place, the level sandy beach near Zwarte 

 Hoek at the base of the rupture. This beach was still narrow though 

 it had possibly increased in size after Treub's visit. Penzig and his 

 companions found there a well-developed Pes-ccjprae-formation, mainly 

 consisting of fpomoea pcs caprae Sw, and Canavajp rosed D. C. - ! ) 

 both common littoral plants in the Dutch Indies; their far-creeping 

 stems often form a loose net-work on the sandy soil '). Between 

 these occurred Viyna marina A/e/r. ; '), a twining, or if there are 

 no supports to twine around creeping Papilionacea, in Java very 

 common on sandy beaches. Two littoral grasses with long creeping 

 stolons were also present, Spinifex littoreus Merr. '') and Ischaemuni 

 riiutlcuni L,; both grasses often form a dense vegetation on the 

 beaches of the Dutch Indies; the first only in very sunny, sandy 

 localities deficient in humus; the second also in shadowed and less 



1 ) Exception should be made for R a c I b o r s k i (t 1917) whose most excellent 

 work, Die Pteridophyten der Flora von Buitenzory (1898), everywhere gives proof of 

 accurate observation and clear insight. 



2) Penrig | Ann. |ard. Bot. Buitenzorg XVII (1(102), p. 97 1 gives the following 

 description of the landing-place: ,,An der westlichen Halfte der Norclseite der Insel 

 ,,wo wir landeten, ist eine schmale Strecke flachen Strandes gebildet '. This proves 

 (see also our map) that he can have visited only the locality near Zwarte Hoek as 

 mentioned by me. I reub also landed on that spot in 1886. From this beach the 

 interior of Krakatao can be reached only over the rocks of Zwarte Hoek. 



3 ) Named by Penzig Canava/ia obtusifolia D. C. 



**) A good reproduction of a photo is found in Ernst, Neue Flora Vuikaninsel 

 Krakatau (1907), plate IV, fig. 7. 



5 ) In Penzig s paper recorded under the names of Vigna lutea and V- luteo/a^ 

 8 ) Named by Penzig Spinifex squarrosus L' 



