58 



When I examined the specimen collected by T r e u b it appear- 

 ed, as might be expected, that the determination was incorrect; the 

 plant is a feeble specimen of Dryopteris setigera O. K., a kremno- 

 phyte rather common in Java from the plains up to an altitude of 

 1800 m; its reproduction is exclusively effected by spores. This 

 species was collected also at the excursion of 1897 and determined 

 by Raciborski as Aspidium vile fesf . (= Dryopteris vilis O. K., 

 most probably only a xeromorphous form of Dryopteris setigera), 

 under which name it is mentioned in the list of P e n z i g *) and 

 by Raciborski 2 ). The well-known Buitenzorg fern-specialist Van 

 Alderwerelt van Rosenburgh determined in 1919 the 

 plants, which Raciborski had found on Krakatao and Mount 

 Guntur and which were recorded by Penzig and Raciborski 

 under the name of Aspidium vile, as Dryopteris setigera. Raciborski 

 calls his plant : ,,eine sehr interessante xerophile 3 ) Art, im Gerolle 



,,am G. Guntur ganze Strecken bedeckend. L Sehr reichlich am 



,,Krakatao wachsend" and Koorders /f ) says of a specimen collect- 

 ed by him on Mount Lamongan ,,Auf einem fast vegetationlosen, 

 ,,etwa 4 |ahr alten, sehr trocknen, felsigen Lava-Riicken". I also found 

 this fern only on steep, rather sterile banks and in localities oecolog- 

 ically similar to these. 



For typical kremnophytes as Dryopters setigera Krakatao was in 

 1886, and much later yet, an ideal habitat; it was found back there 

 also in 1908 and 1919. 



9. Pteris aquilina L. 



At the present time named Pteridium aquilinum Kuhn. This is a 

 halophobous fern, growing (often gregariously) in sunny or slightly 

 shadowed, lime-deficient, as a rule well-pervious and not very fertile 

 localities; sometimes, but rarely, it occurs on steep banks. It propa- 

 gates by ramification of the far creeping rhizomes and by spores 



l ) Ann. lard. Bot. Buitenzorg XVIII (1902), p. 108. _ 



'-) Die Pteridopliyten der Flora von Buitenzorg (1888), p. 173 under the name of 

 Aspidium vile- 



3 ) This statement is not quite correct. G. Guntur receives rather much rain 

 throughout the year. I he 4 driest east-monsoon months have together 20 40 rain-days 

 with a mean fall per rain-day of 10 14 mm. The lava-stream on Mount Lamongan 

 mentioned by Koorders has, on an average, 20 rain-days in the 4 driest months 

 and a mean fall per rain-day of 15 16 m M. Consequently the somewhat deeper 

 parts of the soil and the crevices in the rocks (in which theifern grows) are never 

 very dry and there is no reason to consider the vegetation as xerophilous. One should 

 not confound the dry surface of the rocks with the moist crevices- The fern in question 

 is rather a kremnophyte or a chasmophyte than a xerophyte. 



*) Annotation in Herbarium Bogoiiensi ad Kds 24103 p- 



