VEGETATION OF THE MARSH AND BOG 245 



cluced is insufficient to exert much influence on the 

 vegetation. The consequent absence of well-marked 

 xerophytes forms one of the chief distinctions between 

 the marsh-flora and that of the bog. 



The water of the marsh comes from a wide area, and 

 in the neighbourhood of streams is being constantly 

 replenished, so that plenty of nutritive material is present. 

 The well- nourished plants are quick-growing and tall, and 

 the general aspect of the vegetation differs considerably 

 from that of the bog, where the plants are slow-growing 

 and dwarfed. The difference is well seen in plants which 

 grow in both marsh and bog e.g., the purple moor-grass 

 (Molinia ccerulea), which grows to a height of 4 to 5 feet 

 in Fenland marshes, but rarely reaches 2 feet when growing 

 in bogs. 



The vegetation is often of a very mixed character, 

 broad- and narrow-leaved plants growing indiscriminately ; 

 but occasionally a narrow-leaved form becomes dominant, 

 and gives rise to a pure association. Thus associations 

 dominated by Molinia ccerulea, Phragmites communis, 

 Cladium Mariscus, Juncus obtusiflorus, and other rushes, 

 or various species of Car ex, are to be met with. Other 

 plants commonly found are : Ranunculus sceleratus, 

 CaltJia palustris, Viola palustris (marsh- violet), Stellaria 

 uliginosa (marsh-stitchwort), Hypericum tetrapterum and 

 H. quadrangulum (marsh St. John's- wort), Comarum 

 palustre (marsh-cinquefoil), Parnassia palustris (grass of 

 Parnassus), various species of Epilobium (willowherbs), 

 Hydrocotyle vulgar is (marsh penny-wort), Valeriana dioica 

 (marsh-valerian), Campanula (Wahlenbergia) hederacea 

 (ivy-leaved bell-flower), Anagallis tenella (bog-pimpernel), 

 Samolus Valerandi (brook -weed), MenyantJies trifoliata 

 (bog-bean), Pedicularis palustris, Orchis latifolia (marsh- 

 orchid), Iris, Triglochin palustre, Osmunda regalis (royal 

 fern), various species of Equisetum and Eriophorum 

 (cotton-grass). 



Small areas of raised ground frequently occur in a 

 marsh, and on these drier parts a different type of vegeta- 

 tion exists. Many of the plants of the river-bank occur 

 (see list on p. 241), together with water-loving plants, 

 like Phragmites, whose deep-seated rhizomes are situated 

 in the wetter ground below. 



In many parts, as in the Fen district, the marsh may 



