Clare Island Survey — Phanerogamia. 10 91 



Ostenfeld lays stress on the prevalence of winds useless for seed 

 introduction, and on the fact that, in contradistinction to truly insular floras, 

 only a small section of the Faeroese plants are adapted for wind-dispersal. 

 (Out of 277 species, 71 1 have small seeds, and only 27 have flying apparatus — 

 total 35-5 per cent, of the flora.) In view of these facts, he cannot admit the 

 efficacy of the wind for bringing in the mass of the flora ; and he is driven to 

 the adoption of the land-bridge hypothesis. 



Warming, advocating wind-dispersal, quotes several remarkable recent 

 instances of the wind-carriage of plants and even of stones, notably one of the 

 transport of Erica and Calluna plants across the Kattegat. 2 But these cases are 

 clearly, and indeed admittedly, exceptional. He points out that the S., S.E., 

 and E. winds of the Faeroes amount to 28 per cent. ; and he thinks that the 

 flora includes " not many species which have seeds large enough, and heavy 

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

 includes the whole crux of the problem, and is referred to, in the light 

 of certain experiments, in the succeeding paragraph. He states that he is 

 " fully convinced that the whole of the flora — at least, all the more highly 

 organized land-plants — have immigrated, after the glacial period, across 

 the sea, and from the nearest countries, lying east, especially Great Britain " 

 (p. 681). It need only be added that Wille and Borgesen, for instance, are 

 in agreement with Warming's view ; while Nathorst and Drude, as well as 

 Forbes and Geikie, are advocates of a Faeroese land-connexion. 



Harking back for a moment to the experiments on the actual rate of fall 

 of seeds (see pp. 76-78, ante), let us see what is the chance, as shown by these 

 experiments, of seeds being carried to the Faeroes from" the nearest land — 

 namely, Shetland. Let us again take a very favourable case — seed of the highly 

 efficient Epilobium rnontanum, liberated with a 50-mile-an-hour gale blowing 

 continuously and directly in the right direction. The amount which this 

 seed would need to be raised by abnormal means to keep it afloat during its 

 journey of 3 hours and 36 minutes from nearest point to nearest point would 

 amount to 1'45 mile. But most of even the pappus seeds are not nearly so 

 efficient as Epilobium rnontanum. The many plants with seeds of the Papaver 

 type could not get across unless the seed was raised during the passage by a 

 total amount of at least 22 miles. Yet many of the Faeroese plants have 

 seeds which fall faster than these, and which . would require considerably 

 greater assistance. 



1 This equals vs6 per cent, of ike flora — which may be compared with the figure (17'6 per cent.) 

 arrived at by Clement Reid (Hist. British Flora, p. 21) for the much less insular area of the British 

 Isles ; but we do not know how far the definition of a " small seed " agreed in the two cases. 



2 See E. Warming: Uber Grronlands Vegetation. Engler's Bot. Jahrbucher, s, 18S8-9, p. 407. 



M2 



