180 



Sub-formation of the CJicdk 



*Chry8anthemum Leucan- 



themum o 

 Senecio Jacobsea u 



S. integrifolius (oanapestris) o 



Carlina vulgaris 

 Gnious acaulis 

 [C. arvensis] 

 Centaurea nigra 

 C. Scabiosa 

 Picris hieracioides 

 Crepis capillaris (virens) 

 Hieracium Piloaella 

 Hypochfflris radicata 

 Leontodon hiepidum 

 Sonchus arvensis 

 Tragopogon pratense 

 Campanula glomerata 



Thesium humifusura vi 



[Urtioa dioica] 1 



[Betula alba] 1 



[B. tomentosa] 1 



Fagus sylvatica vi 



Orchis pyramidalis r 



0. maculata vi 



Carex caryophyllea ( = C. 



verna) o 

 C. flacca (glauca) a 



Phleum pratense o 



Agrostis tenuis (vulgaris) 1 

 A vena pratensis la 



[A. fatua] r 



*Arrhenatherum elatius 



(avenaoeum) 1 

 Koeleria gracilis (cristata) a 



The species marked " occur mainly or exclusively in the ditch where 

 the soil is deeper and not so dry. f under trees. The names enclosed 

 in square brackets are those of species clearly alien to the vegetation of 

 the dyke, whether native to the country or not. 



The following species were present in one square metre of the associ- 

 ation examined in detail. The order is that of decreasing frequency. 



Festuca ovina : dominant, in considerable tufts, largely excluding 



other plants. 

 Poterium Sanguisorba ; co-dominant with the last. 

 Hieracium Pilosella : very abundant, especially on patches of bare 



chalk, which it readily colonises. 



