86 



ash-walls, rather big stones ''), doubtless ejected by the crater of 

 Krakatao during the eruption. 



So far Mulder. Boerlage did not make his trip in Oc- 

 tober but a few days earlier, Sept. 29th 1896. As appears from the 

 labels accompanying some of his specimens | i. a. Nephrolepis exaltata 

 Schott and fteris \ itt<jta Z..J he reached the top of the island to 

 which the coolies of the Triangulation Brigade had cleared a path. 

 The collection, which is preserved in the Buitenzorg Herbarium, is 

 rather large: it consists of at least 132 specimens but frequently 

 several of these belong to the same species; the total number of 

 species therefore is probably 2 ) rather less than 100. I cannot share 

 Treub's opinion that this collection gives a complete survey of 

 the Phanerogamic and fern vegetation of the island. On the contrary, 

 data on habitat, altitude and frequence as a rule being lacking (only 

 a few times the labels bear, besides the collecting-number, the word 

 ravine or top, written by a native assistant) it is of extremely little 

 oecological or plant-geographical value. With the aid of the collect- 

 ion one can make a list of names of the plants found, but it gives 

 by no means an idea of the mode of composition of the flora at 

 that time. Moreover it cannot be but very incomplete. It is absolutely 

 impossible to accurately investigate in a single day the innumerable 

 ravines and ridges of Lang hiland. For this purpose weeks, nay 

 months arc required. Boer I age's investigations were probably 

 carried out on the sea-shore near the landing-place and along the 

 path leading from there through ravines and over ridges to the pillar. 

 Faking into account that the perpendicular ravine-walls on Lang Eiland 

 consisted of loose ashes, that they reached up to 50 m. and therefore 

 could not be investigated without special equipment and at the cost 

 of very much time, moreover that the young vegetation of the island 

 must have consisted, besides of a number of common species, of 

 several scattered accidental ones, it is obvious that Bo erl age's 

 collection could not nearly comprise all species occurring in Lang 

 Hiland. And even if it had done so, it would have been of very little 

 value in the absence of all oecological data. 



It is noteworthy but easily accounted for that Boerlage 

 collected on Lang Eiland some species 3 ) which were not found 



l ) Cf. also p. 23, footnote 2. 



-) No list of these species, to my knowledge, being extant, I have not succeeded 

 in finding them all back. For this paper they are of very little importance. 



") i.a- Klumea chinensis D.C,-Blumea lacera D. C.,-Erigeron linifolius 

 Pteris vittata L l ). 



4 ) This species was found by P e n z i g only on Krakatao. 



