CHAP. XLVII LOW-MOOR FORMATION 197 



The water coming from low-moor is rich in calcium and potassium. 

 Low-moors arise not only around reed-swamps, but also at the margin 

 of standing or flowing water whose boundaries they constantly narrow, 

 as the reed-vegetation gradually advances into the water. The moor 

 nearly always commences to form on the side towards the prevailing 

 wind ; waves caused by the wind prevent or obstruct its production 

 on the opposite side. 1 Low-moor is also termed meadow-moor, grass- 

 moor, sedge-moor, lowland-moor, infra-aquatic moor, or swamp-meadow. 2 



FLORA. AND ASSOCIATIONS 



In northern Europe Monocotyledones mostly dominate, and with 

 them many Dicotyledones are intermingled. The following families and 

 genera are represented : most important are the Cyperaceae which often 

 grow in tufts or form a matted covering, and are particularly represented 

 by numerous species of Carex (hence the name sedge-moor 3 or caricetum), 

 but also by species of Eriophorum, Scirpus, Schoenus, and others ; among 

 Gramineae, Aira caespitosa, Agrostis vulgaris ; among Equisetaceae, 

 Equisetum limosum and E. palustre ; many Juncaceae ; Juncaginaceae, 

 including Triglochin palustre ; Orchidaceae, including Epipactis palustris 

 and species of Orchis ; Umbelliferae, including Peucedanum palustre, 

 Angelica, and Archangelica ; Ranunculaceae, including Caltha, Trollius, 

 and Ranunculus ; Rosaceae, including Comarum palustre and Geum 

 rivale ; in addition, Menyanthes, Galium palustre, Epilobium palustre, 

 E. parviflorum, Parnassia palustris, and many others. Mingled with 

 these may be shrubs, including species of Salix, Betula, Alnus, Rhamnus 

 Frangula, Empetrum, and Ericaceae, which grow especially on the turf 

 and drier places. Some European marsh-plants, such as Saxifraga 

 Hirculus and Carex chordorrhiza, are possibly relics of the Glacial Epoch. 4 



Among mosses there are species of Hypnum, Amblystegium, Mnium, 

 Polytrichum, Paludella, and other genera ; but Sphagnum is scanty or 

 absent. 



In Austrian swamp-meadow, according to Gunther Beck, there are 

 thirty-four Cyperaceae, twelve Gramineae, three Juncaceae, also a number 

 of perennial and other herbs, among which eighteen belong to the Mono- 

 cotyledones. 



In various places, according to the dominant plants, we can dis- 

 tinguish various associations, including amblystegieta, cariceta (parvo- 

 cariceta and magno-cariceta 5 ), eriophoreta, molinieta, and others, 6 or, 

 according to species, stricteta, named after Carex stricta, and others. 

 In Greenland, here and there are junceta composed more especially of 

 Juncus arcticus 7 ; similar associations composed of J. effusus, J. com- 

 pressus, and others, also occur in Denmark. 



Beneath and between the latter plants, in low-moor there are usually 

 two storeys ; for, in addition to the humbler perennial herbs which may 

 occur singly, the ground entertains a vegetation of mosses which are 

 an unmistakable sign that there is no circulation of air in the soil. But 



1 Forchhammer, in lectures about 1 860 ; Klinge, 1 890. * See Friih und Schroter, 

 1904. ' ' Graskjar,' i.e. grass-swamp. See Warming, 1 897 ; [see footnote 4, p. 198.] 

 4 See Section XVII, Chapter XCVI. 



6 Schroter und Kirchner, 1896, 1902 ; Brockmann Jerosch, 1909. 

 8 Stebler und Schroter, 1889-92; Hult, 1881, 1887. ' Hartz, 1895. 



