18 



TALKS AFIELD. 



the so-called Red Snow of the arctic regions 

 ^ (^ and high mountains. (Fig. 19.) 

 @ This " snow," which has been so 

 Fig. 19. long regarded with wonder, is an 

 aggregation of immense quantities of a mi- 

 nute red alga, known to botanists as Proto- 

 coccus nivalis. It is almost incredible that 

 at such low temperatures any plant can grow 

 so rapidly. The red snow was known to 

 Aristotle, and was probably observed by him 

 on the mountains of Macedonia. 



Among the visible algce are numbers of 

 species which form the slime on 

 stagnant pools and the green films 

 on flower-pots and boards. A 

 thread of the common zygnema, 

 which makes much of the scum on 

 frog-ponds, is magnified in Fig. 20, 

 and the spiral band of leaf-green 

 which imi:>arts the characteristic 

 color is plainly shown. Every one 

 who has wandered on the beach of 

 the ocean is familiar with numer- 

 ous forms of the higher and larger 

 algae. These curious and often 

 beautiful plants lend a peculiar 

 charm to the sea ; they force upon 

 one the thought that many wonderful pro- 



Fi-. 20. 



