Meadow Association 229 



with the dry uplands that it seemed wise to recognise their 

 individuality by marking them upon the map of the Cam- 

 bridge district. They have been by no means fully indicated ; 

 a considerable portion of the river valleys that have been 

 coloured pink will, with more careful work, in all probability 

 be found to belong to this meadow association. 



The dividing line between these meadows and the very 

 similar meadows bordering the rivers in the fens is by no 

 means so well marked as is the difference between the upland 

 vegetation and the meadows themselves. The grasses are 

 usually of better quality; Deschampsia coespitosa is rare, 

 whilst LoUum perenne, Hordeum secalinum, Cynosurus crista- 

 tus, Alopecurus pratensis and Festuca elatior are common. 

 Such plants as Eroph'da rulgaris D.C., Aral) is kirsuta, Car- 

 duns nufrins, Senecio Jacobaea and Hole us huiatus, typical 

 of the fen meadows, are either very rare or absent in the 

 valley meadows. 



Originally the transference must have been very gradual, 

 as is shown by the isolated fens which have been already 

 briefly mentioned. But just as the fens under man's influence 

 took on the general character of cultivated land, and those 

 portions which now appear as meadow support upon the peaty 

 soil a crop of poor grasses and thistles, so on the other hand 

 the valleys which were but arms of the fen stretching inland, 

 having a clay soil, support naturally the finer grasses like 

 Lolium. 



The flora of these meadows calls for but little attention ; 

 in the ditches Glyce-ria fluitans and Veronica Beccabunga 

 are the two most common plants ; in the meadows themselves 

 the hybrid between Festuca elatior and LoUum jwenna may 

 occasionally be found. 



In some of the less completely reclaimed spots, as at Cow 

 Fen and Dernford Fen, may be seen some of the remains of the 

 old flora, confined to ditches and small ponds in the former, 

 but in the latter in a small piece of damp land by the railway 

 embankment as well. 



