354 PLANTS, SEEDS, AND CURRENTS 



The last great lesson it presents is shown in the support it gives 

 to the views of Bentham and Hooker on plant-distribution. It is 

 not easy to be original in any field where they have laboured. Though 

 the ground has been " pegged out " by them and others, the " claims " 

 are often still unworked. 



Supplementary Note on the means of dispersal of the Carices and 

 the Peat-mosses : — 



The Distribution of the Carices by Birds. — It will have been 

 noticed in the previous discussion that it has been assumed that species 

 of Carex and Sphagnum can follow along the length of the continents 

 from the north polar regions to Fuegia, South Africa, and Australia. 

 In the case of Carex it is well known that the hard seed-like fruits 

 occur in birds' stomachs, and it has been shown that the smaller 

 fruits can be carried in dried mud adherent to their feet and legs; 

 but the question arises whether birds do actually travel along the 

 routes that have been taken by these plants. It has before been 

 observed that certain South African Carices must have been derived 

 from the northern hemisphere, the possibility of their having come 

 •across the ocean from South America, or even from Australia, being 

 -excluded by their absence from those regions. This offers a critical 

 case, and to some extent we are able to meet it. 



Thus, three instances have lately been recorded of swallows 

 captured in Natal and in the Orange Free State, which had been 

 *' ringed " in Great Britain (Staffordshire and Ayrshire) nineteen, 

 nine, and four months previously (Scotsman, November 8, 1913; 

 Times, March 12, 1915). In the Times of the same date reference 

 is made to a Sandwich tern, " ringed " in England in July, which 

 was found on the Ivory Coast, West Africa, in the following February. 

 Then we have the numerous examples of storks marked in East 

 Prussia and the neighbouring provinces which were recovered in the 

 Transvaal, Natal, Basutoland, and Cape Colony. I am quoting here 

 from a paper by A. L. Thomson, who discusses in the Proceedings of 

 the Royal Physical Society of Edinburgh for March 1911, the results 

 of the German and Hungarian inquiries. Doubtless these facts could 

 "he largely increased; but they are sufficient to show that birds do 

 actually make periodical migrations from Europe to South Africa. 



The Distribution of the Peat-mosses by the Winds. — It is 

 not unlikely that the spores of Sphagnum would be sometimes carried 

 in the dried mud adhering to migratory birds; but here the wind 

 presents itself as probably a more effective agent. This being so, 

 we are at once met with the question whether islands like the Hawaiian 

 (that lie in mid-ocean some 2000 miles from the nearest continental 

 •coast, would have received their Sphagna through this agency. The 

 subject of the transport of seeds and spores by wind is discussed at 

 length by Mr. Lloyd Praeger in a recent paper in the Proceedings of 

 the Royal Irish Academy (1911), and I have dealt with it in this work in 

 connection with the Azores (Chap. XIX). Here it may be stated that, 

 as indicated by his experiments on the falling rate of seeds, even 

 the dust-like seeds of orchids could not be carried to Hawaii by a 

 wind moving fifty miles an hour unless they were raised at the start 



