57 



* 



Raciborski ') gives as habitat ,,an feuchten, schattigen Schlucht- 

 ,,wanden" and the no less reliable Post humus 2 ) says: ,,ln primary 

 ,,forest, on and between large rocks in the shadowed beds of small 

 Drivers". Consequently it is very improbable that Treub should have 

 found this fern in 1886 on the lower parts of Krakatao which were 

 then everywhere very sunny and where consequently in the east- 

 monsoon the upmost layers of the soil often became very dry or, at 

 least, were not very humid. Never was this plant found back on 

 Krakatao. When I examined the fern-materials collected in 1886 by 

 Treub, it became evident that the constant appearance of this 

 species in the list of plants found on Krakatao, even in those com- 

 posed by authors *) who had continually free access to Treub's 

 materials, is only due to incorrect reading. B u r c k, who determined 

 1 reub's ferns, did not name this plant N. calcar<itum, but, and 

 correctly, N. cucullatum, a name absent in the lists given by I r e u b. 

 This last-named plant (at present named Dryopteris unite O. A.) is a 

 heliophilous, mesophilous fern of often rather sterile localities. In Java 

 it is ,,eine sehr gemeine Art der sonnigen Stellen der Ebene und 

 ,,des Hiigellandes, seltener in der unteren Oebirgszone, z. B. in dem 

 ,,Ger6lle des O. Guntur" 4 ); in 1886 it found on Krakatao many ideal 

 habitats and also in later years it was found there at every excursion. 



8. Nephrodium flaccidum Hook. 



This plant, at present named Dryopteris flaccida O. K., is a ter- 

 restrial fern of humid, well-shaded localities; in Java it has not yet 

 been found beneath an altitude of 1000 m. Raciborski "'), who is 

 always very reliable, calls if ,,ein gewohnlicher Hrdfarn der unteren 

 ,,und besonders der mittleren Gebirgszone, an schattigen Waldstellen 

 ,,wild wachsend" and I also found it exclusively in such-like localities. 

 Hence it is very improbable that Treub should have found it in 

 1886 on the lower, then still treeless and shadowless parts of Krakatao. 

 In the list of P e n z i g '') it is mentioned, without any comment, as 

 not having been found back. 



1 ) Die Pteridopliyten der Flora von Buitenzorg (1898), p. 170 under the name of 

 Aspidium calcaratum Rl- 



^} O. Posthumus, Betreffende de Pteridophyta van Diainbi in Verslagen Kon. 

 Akad. van Wetenschappen XXXVII, p. 81. 



s ) Docters van Leeuwen, Hnndelingen Eerste Ned.-lnd. Natuurw. Congres 

 1920, p. 7.-); Ann. |ard. Bot. Buitenzorg XXXI <K>2i) p. 239. 



') Raciborski. Die Pteridopliyten der Flora von Buitenzorg ('1898), p. 184 

 | under the name of Nephrodium cucullatum (HI) Baker]. 



') Die Pteridopliyten der Flora von Buitenzorg (1898), p. I7(> under the name of 

 AspiJiuni f/accidutn /$/ 



) Ann. lard. Bot. Buiteniorg XVIII (1902), p. 108. 



