CHAP. XLix HIGH-:\IOOR FORMATION 205 



mountains, because high temperature greatly favours the decomposition of 

 organic bodies. On parts of the east coast of Brazil where rain-forest 

 prevails, cushions of Sphagnum occur in moist places, but probably no 

 peat is formed. From subtropical lands with winter rainfall high-moor 

 is also excluded. The production of peat is most active in lands of 

 moderate temperature and high humidity. In arctic countries it is scanty 

 and feeble, mainly because the amount of vegetation is small ; in Green- 

 land peat is formed from Webera nutans and Hypnum stramineum ^ ; it is 

 produced in Siberia (though not in such quantity as near the Baltic 

 Sea),- in Spitzbergen,^ in Vaigach, and on Tierra del Fuego ; on Antarctic 

 islands extensive sphagneta occur, and there is a production of peat. 



The proper domain of high-moor is the cold-temperate coniferous zones, 

 and west parts of the dicotylous forest-zone where the chmate is oceanic. 

 The dicotylous forest-zone in the eastern part of continents (Asia, America) 

 is unfavourable to high-moor, because of high temperature in summer 

 and low relative humidity of the air. High-moor is rare in the eastern 

 parts of the United States. In the steppe-regions of Russia high-moor 

 occurs here and there in clumps of pine-forest.^ 



High-moor is especially widespread in the northern parts of the coni- 

 ferous belt of Russia and Siberia.^ South of the limit of forest the main 

 part of the country is largely devoid of forest. The soil is frozen nearly 

 throughout the year, and cannot be drained of water during the short 

 summer. Only in the vicinity of river-valleys is the soil dry, because 

 here it is possible for the water to flow away rapidly. The slopes of 

 the valley are therefore clothed with mesophilous forest, next to which 

 comes moor-forest with stunted spruces and birches, and this passes 

 over into vast plains clothed with high-moor. 



True high-moor does not proceed far beyond the limit of forest. In 

 the tundra-domain. Sphagnum is characteristic of the depressions that are 

 constantly covered with water. On the peat-ridges standing above water 

 Sphagnum plays only a subordinate part.'' 



In cold-temperate parts of the Southern Hemisphere for instance, 

 in Patagonia and Tierra del Fuego high-moor is composed of Sphagnum. 

 Azorella, Carex, Empetrum rubrum, and others.' Even in northern parts 

 of the west coast of Patagonia it becomes rare as the atmospheric precipita- 

 tions in summer become less frequent.^ New Zealand has alpine moors 

 that are characterized by a number of Antarctic genera.^ 



CHAPTER L. MOSS-TUNDRA OR MOSS-HEATH 



The tundra is a large flat or gently undulating tract, devoid of forest, 

 and occurs in the north of Russia and Siberia ; the ' barren ground ' in 

 North America is perhaps mainly tundra. The original word is Finnish, 



' Warming, 1887. ' Middendorff, 1867; Pohlc, 1903. ' Nathorst, 1883. 



* Kusnezow, 1898. 



* Middcndorff's ' Schwappendc [soaking] Tundra ' ; sec also Pohlc, 1903. 

 ' See Chapter L. ' Alboflf, 1902. ' Dusen, 1905. 



" Diels, 1896. Regarding the more recent hterature dealing with high-moor, 

 the cited works by Friih and Schroter, Weber, and W. G. Smith should be con- 

 sulted. 



