INSULAR FLORAS. 39 



much of the island as was left after the great volcanic 

 eruption was covered with ash of such intense heat as to 

 destroy absolutely all vegetable life. The substance of Dr. 

 Treub's paper has already been given in English -, 1 there- 

 fore it will be sufficient to mention the leading facts. 

 We have it on good authority that the whole island was 

 covered with a layer of burning pumice-stone, ranging from 

 one metre to sixty metres in thickness. Further, at the 

 time of Dr. Treub's visit, there was no possibility of the 

 new flora being in any part the result of human agency ; 

 and the composition of the new flora was such as to preclude 

 the possibility of its being derived either from the former 

 flora of the island, or from direct or indirect introductions 

 by man. Dr. Treub traces the new vegetation from a thin 

 film of various species of Lyngbya and other Cynophycece, 

 acting chemically on the pumice-stone and preparing it 

 for a fern vegetation, partially succeeded at that date 

 already by a number of flowering plants. About a dozen 

 species of ferns had established themselves, and some of 

 them were abundant, whereas the flowering plants were 

 limited to a few scattered individuals. The seeds of 

 various common littoral plants were observed on the 

 shore, and a few young plants of Erythonia sp., Calo- 

 pliyllum Inophyllum, Ce?'bera Odollam, Hernandia sonora, 

 Ipouicea biloba, and two or three others, all of which, 

 doubtless, owed their presence mainly to the action of 

 the waves. The few plants found on the mountainous 

 interior were, with the exception of one grass, Gymnathnx 

 elegans and Sccevola Kcenigii, of different species, the seeds 

 of which were conveyed by wind or birds. Four out of 

 eight were composites, two grasses, and the other two 

 Sccevola Kcenigii and Tournefortia argentea. It may be 

 added that the island is distant ten, twenty, and twenty-one 

 geographical miles from the islands of Sibesie, Sumatra and 

 Java respectively, the nearest points on which there was 

 vegetation. 



1 "The New Vegetation of Krakatoa, : ' W. B. Hemsley, Nature^ 

 xxxviii., 1888, p. 344. 



