IT A MUSHROOM ? 



sition of the rocks by the action of the sun and breezes of 

 spring. But this opinion was overthrown by Captain Ross, 

 who, in 1819, found red snow in Baffin's Bay (lat. 85 54' N.), to 

 a depth of thirteen feet, over a soil perfectly free from mica. 

 Other explorers affirm that in those regions they have never 

 met with the red snow more than three to four inches deep. 

 Captain Parry, in his Polar voyage, found this coloured snow 

 principally in the track of his sledges j and, agreeing with Sir 

 John Ross, he supposed it to derive its redness from the 

 presence of a kind of mushroom, of the genus Uredo, to 

 which Bauer has given the name of Uredo nivalis.* Accord- 

 ing to experiments made by Bauer on specimens brought from 

 the Polar regions, these tiny mushrooms are, on the average, 

 a fiftieth of a millimetre in diameter they develop themselves 

 like vegetables ; the youngest are sometimes colourless ; when 

 entirely freed from snow, they grow black under the influence 

 of an intense cold, without losing their germinative faculty, 

 and give birth, under the influence of a higher temperature, 

 to a green matter. 



Let us continue to examine the difference of opinion between 

 naturalists. 



De Candolle declared the red snow of the polar regions to 

 be identical with that of the Alps, after having carefully com- 

 pared the two. But he saw in it a genus of cryptogams, 

 differing from the genus Uredo.\ Robert Brown asserted that 



* Annales de Chimie et de Physique, vol. xxvii., p. 134. 

 t Philosophical Transactions, 1820, vol. ii., p. 165. 



