202 OXYLOPHYTES sect, vi 



Among the species concerned are Sphagnum cymbifoHum, S. fuscum, 

 S. Austini, S. rubellum, S. teres, S. recurvum, S. medium, which produce 

 different varieties of sphagneta and often show a zonal distribution. 



On the soft loose soil formed by Sphagnum there are other plants, 

 including some species found on low-moor ; but the flora is scarcely so 

 rich as on that. Species with traveUing-shoots are especially abundant, 

 in accordance with the loose nature of the substratum. The constituent 

 plants must all of them live chiefly as saprophytes. Among other mosses are 

 species of Polytrichum, Aulacomnium, Bryum, Paludella, Dicranum, and 

 others ; among liverworts, Aneura, Cephalozia, Jungermannia ; in some 

 cases lichens also occur ; among Cyperaceae in North Europe, Rhynco- 

 spora alba, several species of Carex and Eriophorum (especially E. 

 vaginatum), and Scirpus caespitosus ; among grasses, Molinia caerulea, 

 Agrostis canina, and others ; among other Monocotyledones, Narthecium 

 ossifragum, Scheuchzeria palustris, Triglochin palustre ; among Dico- 

 tyledones, Ericales are particularly frequent, and include Vaccinium 

 uliginosum, V. Oxycoccos, Vaccinium Vitis-Idaea, Andromeda polifolia, 

 Ledum palustre. Erica Tetralix, Calluna vulgaris (this last-named species, 

 though scarcely ever absent, spreads particularly when the moor has 

 become high and very dry, and then is so abundant that the moor is 

 essentially a calluna-moor) ; in addition, there are Rubus Chamaemorus, 

 Drosera, Pedicularis sylvatica and Cornus suecica ; among woody plants, 

 Empetrum, Myrica Gale, Sahx repens and Betula odorata. On older, 

 higher and drier moors are found pines, including P. sylvestris and 

 especially P. sylvestris var. turfosa, also P. Pumilio ; these are deformed 

 and produce low woodlands, like the elfin-woodland on alps.^ 



In other countries entirely different genera and species are encoun- 

 tered : in North America, Kalmia, Sarracenia, Darlingtonia, and others ; 

 one of these, Kalmia angustifolia, has become completely naturalized in 

 Hanover. But in all oecological essentials the North American is similar 

 to the European high-moor.^ 



Duration of life.- Nearly all the constituent species are perennial. 

 In addition to some parasitic Rhinantheae only Cicendia filiformis and 

 a few other species are annual. 



Concerning construction of shoot any general statement is scarcely 

 possible. 



Different associations of the moor are formed according to the pre- 

 valence of Cyperaceae, such as Eriophorum, dwarf-shrubs such as Calluna 

 and Betula nana, or trees. 



The associations are usually zonally distributed round the water- 

 basins which may occur in the moor ; for instance, a caricetum next to the 

 water may be succeeded by an eriophoretum, and that by a callunetum, 

 and so forth, until the series may conclude with a cladinetum or the 

 hke.3 



On Sphagnum-moor only those species can grow which are capable 

 of following the growth of these mosses, just as on shifting dune-sand 

 the only species that can succeed are those capable of permeating the 

 over-lying sand. As the lower parts of the plants are gradually overgrown 

 by Sphagnum and give rise to peat, their remains become buried. Peat 



* See Chapter LIII. ^ Ganong, 1897 ; MacMillan. 1893, 1896. 



" A. Nilsson, 1899; MacMillan, 1896, 1897, 1899. 



LV 



