64 PASTURE STUDIES: SOME RESULTS. 
such plants as Ranunculus repens, Bellis perennis and Cynosurus 
cristatus were so poorly represented on Area 7, and in the case of 
the two former plants, on Area 6. 
THE EFFECT OF ALTITUDE, SLOPE, ASPECT, ETC. 
Since, as shown above, the two groups of areas differed very 
greatly in what appear to be more important respects, the 
influence of these factors. can not accurately be estimated. The 
most marked differences that may be traceable to these are, that 
Festuca rubra is very prevalent on Areas 1-4, but negligible on 
Areas 6-8, and that both Agrostis alba and A. tenuis occurred on 
the former areas and only 4. ¢enwzs on the latter. 
THE EFFECT OF CULTIVATION, 
Areas 6 and 7 were similarly treated throughout their period 
of cultivation, so that the effect of this can not be seen in their 
case. At the same time, it is very difficult to believe that the 
great difference between the herbage of the two areas was entirely 
due to the difference in the composition of the seeds-mixtures, 
but there is no evidence te the contrary. 
From the results for these areas, one point in particular 
becomes prominent, viz., that the inclusion of a cleaning crop is 
not necessarily the only means of eradicating undesirable plants. 
As will be seen from a comparison of the results for Areas 6 and 
8, the disappearance of the grass-heath plants from Area 6 was 
remarkable. In particular, the suppression of Agrostis tenuis may 
be noted, as this grass is generally considered to be perhaps the 
most difficult of all toget rid of. Thus, although the writer has 
several times used the words “imperfectly cleaned” to indicate 
land which had not been under a cleaning crop, the distinction 
does not seem to be absolute. 
Areas 1, 2 and 3 were not cultivated in exactly the same 
way. Even Area 2, however, although it had not been under a 
cleaning crop, had been carefully cleaned as far as growing cereal 
crops in succession allowed. On these areas, some results, such 
as the greater promineace of Festuca rubra, and the occurrence of 
