How to Know the Lichens and Mosses 



MARSH BUILDING ON MOUNT MARCY 



Upon the open summit of Mount Marcy, 5.344 feet above sea 

 level, there are two small marshy areas. One is a decided 

 depression in the northeast slope; the other is on the eastern 

 slope and nearer the summit. The water necessary to maintain 

 the character of these marshes is probably supplied in part by 

 rainfall, and in part by melting of snows which have accumulated 

 in the crevices of the rocks above. The two marshes are cold 

 botanical gardens of natural formation, unique indeed, as there is 

 no evidence that the soil for them could have been brought from 

 other sources, while everything suggests that the mosses and 

 lichens at the present time growing on the bare surfaces of the 

 rocks are active soil-makers. The boulders of the summit are 

 variegated by the different colours of the lichens growing on 

 their hard and almost naked surface. The rock beneath the 

 lichens is more soft and scaly than elsewhere, and the moss tufts 

 have the spaces between their lower stems and leaves filled with 

 dirt and sand. The soil in most places is but a few inches deep, 

 and largely composed of dead vegetable matter. Only plants of 

 the most hardy nature are found here, and these are small and 

 imperfect representations of similar plants growing at lower alti- 

 tudes. The total number of species found on the summit is 206, 

 of which 103 just half of the total number are dependent for 

 their existence on the other half, the Lichens, Liverworts, and 

 Mosses. 



MOSSES WHICH BUILD UP LIMESTONE 



In trickling springs of mountainous regions, and on the lime- 

 stone rocks of Niagara Falls, and in other localities are found 

 mosses which obtain part of the carbon dioxide (C O 2 ) they 

 require by the decomposition of the bicarbonate of lime 

 [H 2 Ca ( CO 3 ) 2 ] dissolved in the surrounding water. The mono- 

 carbonate of lime (Ca C O 3 ), which is insoluble in ordinary water, 

 is then precipitated in the form of incrustations upon the leaves 

 and stems of the plants. Gymnostomum curvirostre, Trichosto- 

 mum tophaceum, Hypnum falcatum, and others which regularly 

 occur in streams arising from springs loaded with bicarbonate of 

 lime [H 2 Ca (C O 3 ) 2 ] in solution become completely incrusted with 

 lime, but go on growing at the tips as the older and lower parts 

 imbedded in lime die off. In consequence, the bed of the stream 



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