yet been reached. In the Indies it is a fact of common occurrence 

 that in a locality deprived of its original vegetation, a new and at 

 first most unstable flora rapidly develops. When a wood has been 

 felled, when an exhausted hooma (dry ricefield) is .left to its fate, when 

 an old tea-plantation of which good crops are no more to be ex- 

 pected, is deserted and gradually turns into jungle, when ravines are 

 fiile-d up by lahars (streams of sand or mud), when a plot of ground 

 is raised by spouting on it mud or sand from the bottom of the sea, 

 when new land is reclaimed from the waters, the areas deserted by 

 culture or newly gained quickly cover themselves with plants. In 

 this case there are always a few species 1 ) especially grasses, ferns 

 and Compos/rue which will predominate within a short time, the 

 sooner as they are more common in the neighbourhood and dispose 

 of better means of transport. But amidst the dominant species there 

 always appear some herbs, shrubs and trees which, at first only 

 accessory, become gradually constant or dominant, whilst the species 

 formerly dominant gradually disappear. He who will make in a such- 

 like locality a study of the development of the new, yet unstable 

 flora has to reckon with this fact. Therefore an extensive investigation 

 of the whole of the locality is required; it is not enough to examine 

 at intervals some small spot where at the time of investigation not 

 a single specimen may occur of species, momentarily accessory, but 

 which have been dominant or constant or will become so in future. 

 Just the same case presented itself at Krakatao. There also, 

 from the very first, a number of accessory species were scattered 

 among the dominant ones. T r e u b already drew attention to the 

 scarcity of Phanerogams in the lower parts of the island as contrast- 

 ing with the great number of Cryptogams. In the older litterature on 

 Krakatao we come across a striking proof of the presence in the 

 island of only locally occurring plants. Treub collected in 1886 on 

 the northwestern side of the island a very conspicuous fern, Ony- 

 cliium siliculosiim C. Chr. (= O. auratum Kaulf.). In March 1897 a small 

 company of botanists, among whom were Treub, the well-known 

 pteridologist Raciborski and Penzig, visited the same side 

 of the island. Of course they tried to find back the plants of T r e u b. 

 On this occasion Penzig and Raciborski followed two different 



') In lava, especially: Ageratum conyzoides L. and mexicanum Sims.-Baltimora 

 recta L. Bidens p/losus L. var. albus Schulz, Clibadium surinamense L. Erechthites 

 hicracifolia Kaf. and valerianifolie Raf., Lupaturium po/fesce/is D.C . Cleichenia laevi- 

 qata Hook, and linearis Clarke, Imperata cylindrica Gfr., Lantana Camara L. Piper 

 aduncum L Saccharum spontancum L. and Tr'ina orientate Bl. On the sea-side 

 often Chloris barbata 6V., Pluchca indico Less, and Paspolum vaginatum Swartz. 



