LICHENS 



That of Goodyera repens weighs only 2077.0^.^00 of a pound, 

 that of Monotropa, -000,000,006 lb. It is no doubt by the 

 wind that the spores of lichens are carried from one 

 mountain to another. On a map of the world the dis- 

 tance from the Arctic to the Antarctic, between the North 

 and South Poles, seems enormous. Moreover, the amount of 

 water, desert, tropical forest, and cultivated land in this 

 extent of country is very great. There are but few rocks 

 on which lichens could manage to grow. And yet of the 

 Antarctic Lichens in the South Polar regions, and which are 

 also European species, more than 73 per cent are found in 

 the Arctic or North Polar regions.^ 



An Arctic lichen spore probably travelled from Scandi- 

 navia to the German and Swiss Alps, another journey took 

 it to the Atlas Mountains, thence to Abyssinia, again to 

 Mount Kenia, and from there, somehow, it wandered to the 

 South Orkneys or King Edward VII Land. 



While talking of lichens, one must not forget the Manna 

 of the Bible {Lecanora esculentd) and two other species, 

 which form warted, wrinkled masses on rocks. It breaks off 

 and may be carried away by the wind, or in heavy rain it 

 may be washed into depressions of the soil, where a man can 

 pick up 8 to 12 lb. in a day. 



It " is used as a substitute for com in years of famine — 

 being ground in the same way and baked into bread. ... It is 

 also remarkable that all the great so-called rains of manna, 

 of which news has come from the East to Europe, especially 

 those of the years 1824, 1828, 1841, 1846, 1863, and 1864, 

 occurred at the beginning of the year, between January and 

 March, i.e. at the time of the heaviest rains. . . . The inhabit- 

 ants of the district actually thought that the manna had 



^ Darbishire, Trans, and Proc. of Bot. Soc. Edin., vol. 23, part 1. 



261 



