1898-1902. No. 19.] STRAY CONTRIBUT. TO THE BOTANY OF N.DEVON. 17 



buted to whalers who may have been here during the time of the whale- 

 fishery in Baffin Bay. It seems strange, however, that they should 

 have undertaken any such work. 



The book of ERNST, quoted above, contains moreover several other 

 points of interest in connection with the problem of immigration here 

 in question. It gives accounts of the three botanical investigations under- 

 taken in the island of Krakatau after the great catastrophe which annihi- 

 lated the old vegetation of the island, August 2627, 1883. The flora 

 of the island consisted, at the first visit, three years after the eruption, 

 principally of plants carried by wind: 6 species of blue-green algae, 

 2 mosses, and 11 ferns 1 . TREUB found, besides, seedlings of 9 species 

 of phanerogams and seeds of some more plants on the shore. During 

 the following years, members of every division of the plant kingdom 

 have immigrated, and ERNST, 1. c., p. 38 45, gives a list of 137 species. 

 Of these, 45 are cryptogamous plants which almost certainly have immi- 

 grated by aid of the wind. Among the 92 phanerogams, 67 (73 %) 

 are halophytes which ERNST thinks have been carried to the shore by 

 sea currents; 9 species (10 %) he reckons as certainly imported by birds; 

 15 species (16 %) as having been carried by the winds. He also gives 

 alternately the latter figures as 18 and 28, when more doubtful species 

 are included. 



Now, indeed, it may seem that I have chosen for comparison, a 

 district of to dissimilar a nature; but I think it may be of some interest 

 to put together these two instances of plant migration. Krakatau lies 

 twenty-two miles from the nearest point of the mainland, and twelve 

 from the nearest island which, however, suffered so greatly from the 

 catastrophe that, for a long time, it was not able to supply much. Still, 

 we have here got 137 immigrated species in less than twenty-five years. 

 But this has taken place in a tropical region containing thousands of 

 species in the flora of the mainlands. If now we exclude all those 

 species which are halophytes and which have most probably been con- 

 veyed by the aid of sea-water, we shall have only 15 (28) species of 

 phanerogams carried by the winds, and 9 (18) transported by birds. 

 Only these and the cryptogams are of interest here as, for various 

 reasons, transport by sea currents is excluded in the Jones Sound islands. 

 We thus see that, even in the tropics, migration by aid of the wind is 

 restricted to spores of cryptogams and to a very small number of seeds 



a ) TREUB, M., Notice sur la nouvelle flore de Krakatau. Ann. du Jard. botan. de 

 Buitenzorg, Vol. VII, 1888. 



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