CHAPTER XIII. 



MOSSES AND LIVERWORTS. 



The mosses and liverworts occupy a very isolated 

 position in the plant world. They differ greatly in 

 appearance from the Fern alliance and are yet exceed- 

 ingly unlike the Algae and Fungi. 



Specimens of some sort of moss may be found in 

 almost every kind of country, for mosses are adapted to 

 every sort of climate and soil. The little black alpine, 

 Andraeas, grow upon boulders and rock under conditions 

 of extreme exposure ; and although they do not quite 

 reach the high altitudes attained by some alpine lichens 

 they are almost as hardy. Alpine streams and water- 

 falls have an abundant moss and liverwort flora ; most 

 peat bogs are formed by the action of Sphagnum. Both 

 mosses and liverworts occur on moors, about the roots 

 of heather, and in pastures, especially when the soil is 

 clayey. Others form a characteristic and important 

 constituent of the " wood-floor," where the graceful 

 Thuidiiun taviariscinuui and other branching, feathery 

 Hypnums of many different varieties, often cover the 

 ground under the trees with a network of green fronds. 

 Some are even submerged plants. Fontinalis antipyretica 

 is found growing under water on stones and rocks in 

 rapid streams where, in order to maintain its position, 

 it has to resist the full strength of the current during 

 floods. The liverwort Riccia fluitans again is entirely 



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