205 



Occurred chiefly at the south-eastern angle; farther to the north 

 only scattered specimens were present; the grass-jungle lay there 

 either immediately behind the beach or, wherever the Barringtonia- 

 formation had developed, behind the latter. It is however quite 

 possible that the Casuarina- forest has since spread or shifted to 

 the north. 



In 15 hereafter Mr. Docters van Leeuwen states that 

 here and there the grassy plains advanced as far as the littoral zone. 

 Whether from this statement is to be concluded that in these places 

 the Casuarinas were lacking is not clear; sometimes it seems that 

 Casuarina equiseti folia, which is considered by' 1 ) Schimper as a 

 component of the Barringtonia-iormation, but which had better be 

 regarded as making a formation of its own is by Mr. Docters 

 van Leeuwen not even considered as a littoral plant (Cf. 15). 

 I cannot agree with the author where he says that on Krakatao 

 Casuarina equisetifotia replaces the fringe of coco-palms ,,on other 

 ,,islands". Wherever coco-palms are found on those other islands 

 they have originally been planted and, as a rule, not in ,,a fringe" 

 (though it may seem so when seen from afar) but in several rows 

 and at some distance from the sea. Only where the beach gets 

 washed off by the waves, coco-palms may be found immediately 

 along the border of the sea. Casuarinas on the contrary are never 

 cultivated on coral-islands ' 2 ), but grow spontaneously on well-pervious 

 beaches rich in lime such as are regularly found on such islands. 



In 1906 the highest Casuarina on the south-eastern side of 

 Krakatao measured about 25 m. Mr. Docters van Leeuwen calls 

 the trees in 1919 quite tall and robust but gives no figures. But in 

 a paper a ) published one year afterwards he says that the tallest 

 trees were more than 33 m. high. I myself found Casuarinas of about 

 that size already in 1908 4 ). As plants entirely overgrowing the 

 tall Casuarinas are mentioned Ipomoea denticulata Ciiois., 1. longiflora 

 R. Br. and Colume/la trifolia Merr. This cannot possibly be correct. 

 Ipomoea denticulata is a comparatively slender twiner, which never 

 reaches a great height; it cannot have entirely overgrown tall Cast/- 



!) Schimper, Indo-Malayische Strandflora (1891) p. 69. 



2 ) Only on the calcareous island of Madura I saw on the sand-dunes of Batang 

 batanq daia a wood of Casuarina equiseti folia, planted by the natives. 1 he trees were 

 all polled quite beneath; the young shoots were regularly cut off for fuel. 



3 ) W. Docters van Leeuwen. The galls of Krakatau and Verlaten Eiland 

 in Ann. |ard. Bot. Buitenzorg XXXI (1921), p. 62. 



4 ) See herebefore, p. 187, and laarverslag van den Topographischen Dienst in 

 Nederlandsch Indie (Year-book of the Topographical Survey Service in the Dutch 

 Indies) 1908, p. 190. 



