48 



T r e u b, because their identity is not established and other species 

 of the same family (Kyllinga monocepha/a Rottb., Cyperus kyllingoides 

 Vahl,~C. sto/oniferus Retz) may have occurred on the beach. Cyperus 

 pennatus and Fimbristylis spat/iacca were in 1897 and in 1906 found 

 on the beach near Zwarte Floek. 



7. Ipomoea pes caprae fy.2> w - 



A plant with very long (up to 35 m.) creeping stems, in the 

 Dutch Indies of common occurrence on sandy beaches, but which is 

 also found in many localities in the interior, far remote from the sea. 

 The reproduction is effected by ramification of the creeping stems 

 and by seeds. The latter possess floating power, because the testa 

 is not entirely filled up by the germ '); they are also spread by 

 rain-water flowing rapidly down. The beaches of Krakatao offer a 

 very favourable habitat to this species, which was found there at 

 every excursion. 



8. Gymnothrix elegans Biise. 



At the present time named Pennisetum macrostachyum Brongn, 

 a robust, tillering grass, without stolons. The reproduction is effected 

 by fruits which, when ripe, remain enclosed in the spiculae. The 

 latter fall off as a whole and bear at their bases an involucre of 

 very long bristles by the aid of which they may be easily spread 

 over some distance by the wind. The statement of Treub that this 

 grass is common in Java should be understood in this way that the 

 plant is often cultivated there for ornamental purposes; spontaneously 

 growing it has been found in the island only a few times- It is res- 

 tricted to sunny, rather sterile localities; hence it found in 1886 and 

 yet much later, on Krakatao many localities fit to grow in. In 1906 

 it occurred in some specimens in crevices of the rocks at Zwarte 

 Hoek, on the same side of Krakatao where Treub had discovered 

 it 23 years before. It is no littoral plant and, if Treub did really 

 find it on the shore in the oecological sense of the word it must have 

 been in a single specimen gone astray from the interior where Treub 

 likewise found the plant. But probably he comprised under ,,shore" 

 also the quite leached-out older parts of the increasing sandy beach 

 at the base of the steep wall (Cf. p. 36) by which it is secluded 

 from the interior, There or on the wall itself Pennisetum may have 

 grown then as it did in later years. 



') Cf. Schimper, Indo-Malayische Strandflora (1891), p. 1<>3. 



