( 771 ) 



is completely wanting' in the intervening plain, except oii the sea- 

 beach, 30 kilometres olf. Since nioreovei' no argument has been 

 adxanccd in favour of dissemination l)v animals, it would appear, 

 that tlie winds of Central Java are capable of transporting the fruits 

 of Dodoiwea riscosa o\'er a distance of more than 30 kilometres 

 although these fruits weigh 0,040 grams, and have a surface of 2i 

 square centimeters. 



There is, however, scarcely need, to point out here, that great 

 care is necessary ^) in drawing coiiclusions as to transport by wind. 

 I only refer to what has been said above, regarding the wind distri- 

 bution of Acer nlvenm. Notwithstanding the apparent possibility of a 

 direct transport by wind over large distances, I consider that also 

 in the case of Dodoiiaea windtransport in stages is much more 

 probable. 



Its general occurrence on the tropical shores of the whole world 

 is sufficient evidence of the extreuie suitability for transport by water 

 over very great distances, so that no more need be said on this point. 



The extraordinary power of resistance, which I have i-epeatedly 

 observed, against drought of the air and of the soil, against direct 

 sunlight, against the saline contents of the soil and also against strong 

 winds, together with the property of bearing numerous fruits at an 

 early age, which fruits are well adapted to transport by wind and 

 by water (also by sea water) — ■ all these characteristics fully explain, 

 why this tree appears in Java, as the pioneer of new vegetation 

 not only in alpine regions, but also on sandy sea beaches. 



According to what has been said above, the almost complete 

 absence of the species from the broad belt between the beach und 

 the mountains, is probably due, to the crowding out by other plants 

 of such seedlings as may arise from fruits, which doubtless frequently 

 fall in the intervening zone. 



Summarising, it appears to me, that the apparently whimsical 

 distribution of this characteristic Javanese Sapindacea can be readily 

 deduced, with a large degree of probability, from the properties 

 mentioned above, and especially IVom those properties, which are 

 connected with the edaphic condition of the species. 



§ 5. Note on some incompletely known species of Quercus, in 's Ryks 

 Herbarium, at Leiden. 



In KooRU. and Valeton Bijdr. Booms. Java X, 65 there are men- 

 tioned at the end of the description of 25 species af (Quercus, growing 



1) Gompare also Vogler in Schroeter 1 c. 740. 



