36 Pasture Proble^ns 



alba et A. canina. Additional plants are Carex curta, Luzula erecta 

 and L. congesta, Scabiosa Succisa and locally EriojiJiorum angustifolimn. 

 Neglected pastures on well-drained land pass, however, directly 

 into scrub with Primus spinosa, Crataegus Oxyacantha, and Rubus spp. ; 

 whilst intermediate cases are frequent which pass into alder holts 

 with the addition of Molinia and other plants mentioned above. 



IV. THE LATER STAGES IN THE STABILISATION 

 OF GRASSLAND. 



It is only possible to study the relationships of indigenous species 

 on old grasslands (natural and semi-natural) and the later stages in 

 the stabihsation of such pastures by a comparison of types and by a 

 series of deductions. The conclusions to be drawn are as follows : 



(1) That the grasslands of this country conform to a number of 

 well-marked types. 



Our natural grasslands have been largely studied by ecologists and 

 have been partially classified i. The factors which favour the develop- 

 ment of grassland and which make for one type rather than another 

 have been investigated by Smith and Crampton (13). 



Carruthers(5)2 in his work on tended grasslands clearly brought out 

 in his pubhshed data the fact that semi-natural types could be recog- 

 nised. He was, however, chiefly concerned with the agricultural value 

 of species qua species and consequently did not elaborate this aspect 

 of the problem and was himself rather impressed with the ubiquity 

 of the ordinary grasses and clovers. Smith and Crampton (13), further- 

 more, have remarked upon the apparent lack of connexion between 

 habitat and variations in their " Artificial " grasslands. It will, however, 

 be apparent from a consideration of the types here reviewed that the 

 tended classes of semi-natural grasslands differ from each other qualita- 

 tively chiefly in respect of the included miscellaneous flora and the 

 relatively unimportant members of the Leguminosae and less in respect 

 of the ordinary agricultural grasses and clovers, which albeit exhibit 

 very considerable quantitative differences. There is, none the less, 

 rather more quaUtative variation amongst the Gramineae on the poorer 

 types of semi-natural grasslands found wthin Watson's agrarian zone 

 than Carruthers' observations would seem to have suggested. 



1 See e.g. (12) and (19). 



* And to a less extent Fream (7) and (8). 



