154 



VEGETATION OF THE PEAK DISTRICT 



[CH. 



REED SWAMPS 



There being no extensive, shallow, sheets of water in the 

 district, it follows that reed swamps are not common and are 

 not typically developed. The most characteristic member 

 (Phragmites communis) of reed-swamps in general has only, 

 in the course of the present botanical survey, been observed in 

 lower Monsal Dale, where, in the back waters of the river Wye, 

 it forms one or two small associations or societies. However, 

 most of the streams of this hilly district have a fairly strong 

 current ; and this factor of itself is sufficient to account for the 

 paucity of reed swamps of Phragmites communis by the stream 

 sides. It appears to be generally the case that this plant 

 only forms typical reed swamps in stagnant or almost stagnant 

 waters ; and, where the water is well aerated, any reed swamps 

 that occur are dominated by other plants, such as Olyceiia 

 aquatica and Phalaris arundinacea. In this district the two 

 latter plants are frequently dominant in plant societies or 

 small associations up to about 600 feet (183 m.). The latter 

 plant, however, occasionally occurs up to about 900 feet (274 m.). 



The following plants occur in the small and rather non- 

 typical reed swamps of the southern Pennines : it will be seen 

 that many of the species are in this district only of local 

 occurrence : 



