i 9 8 OXYLOPHYTES SECT, vi 



the mosses by no means play the same part as in Sphagnum-moor. 

 Lichens generally do not occur in such places in temperate Europe ; 

 whereas in arctic moors they are sometimes admixed, often on wet spots 

 where they occasionally form pure associations. 



ADAPTATIONS 



Duration of life. The constituent species are mainly perennial and 

 herbaceous ; only a few are woody. Some are biennial ; but annuals 

 are scanty, being represented by parasitic Rhinantheae. During winter 

 the bog shows grey withered leaves and shoots. The spring sets in late 

 because of cold due to the abundance of water and to evaporation, also 

 because of cold air above depressions in the ground ; but certain early- 

 flowering species, including Eriophorum vaginatum, provide exceptions 

 to this rule. 



The form of shoot varies greatly in this rich flora. Any general type 

 of adaptation can hardly be proved to exist. Among dominant Mono- 

 cotyledones some produce dense, tall tufts ; this is the case with Carex 

 stricta, which sometimes forms a zone, a ' strict etum ', outside the reed- 

 swamp on the landward side, and shows between its tufts open water 

 until this is occupied by other vegetation. 1 These bogs, in contrast to 

 reed-swamp, entertain many caespitose plants, such as species of Carex 

 and of Gramineae. 



Runners and travelling-rhizomes are possessed by an abundance of 

 species, including Equisetum palustre, Carex Goodenowii, C. panicea, 

 C. gracilis, C. acutiformis, and Menyanthes. 2 The runners and rhizomes 

 above the soil or water are often woven together with numerous roots 

 to form a coherent mat. 



Meadow which consists of grasses, but whose soil is neutral in reaction, is closely 

 allied to caricetum : it will be discussed in connexion with mesophilous com- 

 munities. The amount of water most favourable to it is apparently 60-80 per cent., 

 whereas for arable field 40-60 per cent, suffices. Caricetum contains an amount 

 of water exceeding 80 per cent. ; the water-table of meadow in summer stands at 

 a depth of 15-30 centimetres. 



Moss-bog. Sometimes mosses, including Aulacomnium, Hypnum cuspi- 

 datum, and others, preponderate over flowering plants. In such cases there 

 arises a dense, soft carpet of moss, with isolated flowering plants, lycopods,' 

 and lichens scattered here and there. Moss-bog of this kind occurs in 

 Arctic and Antarctic countries 3 ; it merges into moss-tundra as well as 

 into Sphagnum-bog, that is to say into Polytrichum-tundra and Sphagnum- 

 tundra. 



By the word ' myr ', employed in Norway and Iceland, we under- 

 stand any kind of moor. And in Norway a distinction is drawn between 

 grass-moor 4 (bog-moor) and moss-moor, the latter of which is a high- 

 moor. The grass-moor [sedge-moor] probably nearly always has a carpet 

 of mosses (Paludella, Amblystegium, and others) and a covering, half a 

 metre in height, of Cyperaceae (Carex chordorrhiza or C. filiformis). 



1 The ' Zsombek-formation ' of Kerner, 1858. * See Yapp, 1908. 



1 'Meadow-moor' of Brotherus ; see also Warming, 1887; Dusen, 1905, 

 p. 403. 



* [Here the Norwegian, like the German, word ' Gras ' is definitely applied not 

 only to grasses, but also to sedges. Hence the English version should be ' sedge- 

 moor '. P.G.] 



