10 f i6 Proceedings of the Royal Irish Academy. 



a few hundred yards. Their results correspond with those ohtained by 

 Loew 1 from similar observations in Germany. 



To take a case from the Tropics. Eidley 2 finds that the winged seeds of 

 tall forest-trees in the Malay Peninsula are earned by strong winds only 

 from 10 to 60 yards from the parent. Plumed fruits and seeds are more 

 efficient., and powder-seed still more so. He points out that in tropical insular 

 floras plants which possess winged seeds constitute only 2 per cent, of the 

 flora, and plume-seeded species are also extremely rare. The proportion of 

 powder-seed plants in oceanic islands is usually very large, even if cellular 

 plants are excluded : " Powder-seed has the most rapid transit probably of 

 any form of seed, and is most widely diffused." 



Vogler, 3 in a searching paper on the dispersal of plants in the Alps, 

 advocates long-distance dispersal. He considers wind-carriage of seeds for 

 hundreds of kilometres a possibility, and carriage of from 3 to 20 kilometres 

 of practical importance in seed-dispersal. It may be pointed out that most 

 of the examples on which he bases his conclusion are leaves, such as those of 

 the Beech, which have been carried high up the mountains or over considerable 

 distances. Similar eases are quoted by Beauverd. 4 But withered leaves are 

 much less perishable than most flying seeds. Leaves may be blown along the 

 ground for considerable distances easily and without injury, and in windy 

 weather may make a whole series of flights : the ring or group of hairs that 

 form the flying mechanism of the larger wind-dispersed seeds are, on the 

 contrary, easily injured, and easily entangled; and their efficiency is probably 

 almost always confined to a single flight in dry weather, as Bentham long 

 since pointed out. Yogler's other instances relate to the transport of com- 

 paratively heavy bodies by hurricanes or whirlwinds. Such phenomena, 

 while they undoubtedly occur, and may even be frequent in alpine regions, 

 have probably very little practical bearing, though they show that wide 

 dispersal of even heavy seeds by the wind is not beyond the range of 

 possibility. Staufl'acher's case, quoted by Yogler (Joe. cit., p. 90;, in which new 

 plants appeared in an isolated valley where they had not been seen before, 

 is, to my mind, vitiated by the impossibility of proving the negative which he 

 arfirms. Seeds buried in the soil, which unquestionably retain their vitality 



1 E. Loew: Anfange epiphylischer Lebensweise bei Gefasspflanzen Xorddeutstblands. Yerbandl. 

 d. bot. Yereins der Prov. Brandenburg, vnriii, pp. 63-71. 1892. 



* H. X. Eidlet : On the Dispersal of Seeds by the Wind. Annals of Botany, xix, pp. 351- 

 363. 1905. 



3 Paul Yoglee, loc. cit. 



4 Gustave Beauteed : Quelques cas de dissemination des graines par le rent. Bull. Herb. 

 Boissier, (2), i, pp. 633, 634. 1901. 



