10 92 Proceedings of the Royal Irish Academy. 



In view of these facts, it seemed difficult to endorse Warming's view 

 already quoted, that few Faeroese plants " have seeds large enough and heavy 

 enough to prevent them being carried along by a gale." 



The Case of Krakatau. 



The interesting case of the flora of Krakatau has been made widely 

 known by the publication of Ernst's recent book, and its translation into 

 English. 1 The vegetation of this island and an adjacent islet, as well as a 

 considerable portion of the land-surface of Krakatau itself, was wiped out by 

 a terrific eruption in 1883, which submerged portion of the island, and 

 covered the remainder with a layer of hot pumice and ash averaging thirty 

 metres in thickness. Verbeek's party, visiting the island two months later, 

 could find no trace of vegetation left. In 1886 Treub found on the island 

 fifteen Phanerogams and eleven Ferns, divided into two almost independent 

 groups, the strand flora and the flora of the interior, the inland flora con- 

 sisting of numerous Ferns (eleven species) and in small quantity eight 

 Phanerogams. The island was again visited by Treub and others in 1897, 

 when fifty-six Phanerogams and twelve vascular Cryptogams were found, 

 the ground being now in some places completely covered with vegetation. 

 The visit of Ernst and his party in 1906 showed that the number of Phanero- 

 gams had risen to 92, and that a dense vegetation was re-established. It is 

 held by Treub and Ernst that the entire new flora immigrated since the 

 eruption, by means of water, air, or flying creatures. The only loophole of 

 escape from this conclusion has been pointed out by ScharfP — namely, that it 

 was not (nor indeed could it be) proved that vegetable germs had not survived 

 the eruption. It is quite true that Treub, as a result of his visit in 1886, is 

 positive on this point. " En premier lieu il est indispensable de prouver que 

 la flore actuelle doit etre considered comme nouvelle et qu'elle n'est pas issue 

 des restes de la vegetation luxuriante qui occupait 1'ile avant l'eruption. 

 Eien n'est plus facile d'ailleurs que de fournir cette preuve. Lors de 

 l'eruption les arbres terrases ou brises par de violentes rafales ont dri etre a 

 moitie carbonises, vu le temperature extremement elevee qui a certainement 

 regn^ sur toute Hie. En suite Krakatau a etc" couvert, depuis le sommet 

 j usque bien au de la du niveau de la rner, d'une couche de cendres et de pierre 

 ponce brulantes. Cette couche a une epaisseur variant entre un metre et 



1 A. Ernst ; The New Flora of the volcanic Island of Krakatau. Cambridge, 1908. 



2 R. F. Scharff : On the Evidences of a former Land-bridge between northern Europe and 

 North America. Proc. R. I. Acad., xxviii, Sect. B., pp. 8-9. 1909. 



