262 SUCCESSION IN EURASIA. 



found in the Festuca zone. The doDMnant plants of the fourth zone are 

 Armeria maritima, Silene maritima, and Agrostis maritima. The High Elbow 

 is characterized by Lotus, Rumex, Plantago, Armeria, and Poa pratensis. In 

 the salt-marshes, the pioneer, after the algae, is Salicornia. In the next stage, 

 Salicornia europaea, Aster, Glyceria, and Statice limonium are characteristic. 

 In later stages, Salicornia is still abundant, but Statice, Triglochin, Armeria, 

 Plantago, Spergidaria, and Aster are all common. At this stage, Obione enters 

 and it quickly becomes dominant in the older marshes, where Glyceria may 

 still persist successfully. The Glyceria sward becomes a marked feature in the 

 latest stages and other Salicornias replace the earlier S. europaea. 



Matthews (1914 : 134) has described the hydrosere in the White Moss Loch, 

 Perthshire, recognizing the following stages : 



I. Aqtjatic Formation. II. Marsh Formation. 



A. Deep-water association: Elodea. A. Herbaceous marsh association. 



B. ShaUow-water association: Potamogeton, (a) Carex-Menyanthes sub-association. 



Myriophyllum, Chara. (b) Comarum palustre sub-association. 



C. Reed-swamp association. B. Alder-willow association. 



(o) Phragmites communis consocies. 

 (6) Carex ampuUacea consocies. 



MIDDLE EUROPE. 



Friih (1883) has discussed at length the development of peat-moors; 



He concludes that marine peat is unknown, but that algae, Chroococcaceae 

 and diatoms may play a considerable part in forming peat. The growth of 

 Sphagnum, and hence the development of high moor, is regarded as impossible 

 on a calcareous substratum or in "hard" water. Sphagnum high moor arises 

 in lakes and ponds with water free from lime by the development of a Sphag- 

 netum at the margin. This zone extends inward as a floating mass, on which 

 algae, Drosera, Vacdnium, and Eriophorum vaginatum find a footing. The 

 weight is thus increased, and the plant covering gradually sinks. High moor 

 may also arise on impervious clay or sandy soils kept wet by soft water. 

 Meadow moor is developed in waters rich in lime. In deeper places peat 

 formation also begins at the margin by means of Carex, Sdrpus, and Phrag- 

 mites with Hypnum, a floating zone is formed, and later sinks. In other areas, 

 Potamogetonaceae, Juncaginaceae, Alismaceae, Typhaceae, Iris, Utricularia, 

 and Myriophyllum play a part. Meadow moor may also be formed where 

 the surface soil is kept wet with hard water. As to the relationship between 

 the two kinds of moor, the author reaches the conclusion that most high moors, 

 consisting chiefly of Sphagnum, have arisen from meadow moors, so that moors 

 are primarily meadow moors and secondarily high moors, in consequence of a 

 chemical change in the water. 



Klinge (1884) has described the vegetation of the dune region of the Kurisch 

 Peninsula, and has given many indications of the developmental relationships : 



The strand is occupied by the usual halophytes, Salsola, Atriplex, Cakile, 

 Glaux, etc. The dunes exhibit two formations, dune grass and dune forest. 

 In the former, the dominant grasses are Hordeum arenarium, Agrostis stohni- 

 fera, Festuca ovina, Psamma arenaria, Calamagrostis epigeios, and Carex are- 

 naria. The dune forest consists of Pinu^ silvestris. The dune ridges, behind 

 the fore dunes, are covered with pine woodland, beneath which is found 



