270 



already growing on Lang Eiland and Verlaten Eiland. Any visitors of 

 Krakatao, native fishermen as well as Europeans, may have introduced 

 it, neither is introduction by animals to be considered impossible. 

 Nothing definite is known. Lantana camara L. had in 1908 already been 

 found on Verlaten Eiland near the coast. It may have been introduced 

 into Krakatao from there or from any other of the surrounding islands, 

 either by man, by animals or perhaps by the sea. Though the kernels of 

 the fruit do not possess floating power, fruit-bearing branches, carried 

 by swollen rivers to the sea, might have been washed ashore. Here 

 again nobody can tell what has happened. Of the species of Dioscorea 

 the identity is not fully established. Several species of this genus are 

 cultivated in Java by the natives for their tubers which may reach an 

 enormous size and form a not unimportant article of food. In culti- 

 vation the plant is always reproduced by its tubers. As it is not even 

 known which species was found, it is quite useless to speculate on 

 possible modes of introduction. Of the remaining species there are 25 

 ferns and fern-allies, viz. Angiopteris evecta Hoffm., Antrophyum 

 spec., Aspidium melanocaulon Bl., Aspidium spec., Asplenium 

 nidus L., Cyclophorus acrostichoides Presl, Cyciophorus adnascens 

 Prcsl, Daval/ia spec., Dip/aziiim po/ypodioides Bl., Drymog/ossum 

 heterophyllum C. Chr., Dryopteris megaphylla C. Chr., Equisetum 

 dehi/e Roxb., Hymeno/epis brachystachys J. Sm., Hymenolepis spicata 

 Presl, Lycopodium squarrosum Forst,, Lygodium circinatum Sw., 

 Lygodium scandens S\v., Nephro/epis biserrata Schott, Odontosoria 

 chinensis /. Sm., Polypodium accedens Bl., Poly podium heracleum 

 Knze., Po/y podium /ongissimum Bl., Polypodium spec., Schizaea 

 dichotoma Sw., and Trichomanes humile Forst. which may be repro- 

 duced by their very light spores. These may quite well have been 

 introduced by wind, but this is not proven; other means of introduction 

 are possible. It is not even proven that all of them were introduced 

 after 1883. The earth-ferns, and perhaps also some of the epiphytes, 

 may very well be the offspring of plants that had escaped destruction. 

 Nobody knows. One can only guess and authors have repeatedly made 

 hazardous guesses. So has Mr. Docters van Leeuwen done, as 

 he admits himself in the Dutch text of his paper *), in Appendix I, 



V) Dr. W. Docters van Leeuwen in Handelingen Eerste Ned. Ind. Natuurwetensch. 

 Congres, 1920, p. 51: ,,ik heb bi| benadering de verspreidingswijze aangegeven, maar 

 ik heb er dlkwijls een slag naar rnoeten slaan". The English rendering of this text in 

 Ann. |ard. Bot. Buitenzorg XXXI (1921J p. 122: ,,l have stated the manner of spreading 

 ,,with the nearest approach to accuracy I could, but I have often been compelled to 

 ,, guess' , is quite inaccurate. 1 he correct translation runs as follows: ,,I have roughly stated 

 ,,the manner of spreading, but I was often compelled to make quite hazardous guesses". 



