50 PASTURE STUDIES: SOME RESULTS. 
This may be connected with the different treatment given to the 
two areas while under cultivation. 
Rumex Acetosa, 
This was not recorded on Areas 6, 7 and 8, and only in small 
quantities on the other areas. It seems to be most prevalent on 
the young pastures, but the highest Sp. fr. occurred on Area 5 at 
rod years. This is interesting in view of the fact that this was 
the only area recently limed, as it is generally understood that 
“lime applications tend to check its growth” (5). 
Centaurea nigra. 
This plant is recorded by Stapledon as an arable land weed 
at high elevations in Mid-Wales (17), and it is likely that where 
it is fairly strongly indigenous it may survive a period of imperfect 
cultivation, as the writer has found it to have specific frequencies 
of 4, 8 and 8 at 14, 2 and 24 years respectively under such con- 
ditions.* 
It was not recorded on Area 8, and only in minute quantities 
on Areas 6 and 7, but on the other areas it was more plentiful. 
The effect of thorough cleaning of the land is probably seen in 
the relatively low Sp. fr. of 7 on Area 3 at 74 years as compared 
with specific frequencies of 14 and zo at 84 and 104 years respec- 
tively on Area 2, It had but a low Sp. fr. on Area 5 at 10} years, 
but it is generally believed that it is kept in check by grazing with 
sheep. Is is obviously a more important constituent of the 
herbage of the older than the younger pastures under the condi- 
tions prevailing for Areas 1-5. 
Plantago major. 
This was but poorly represented, but it is shown to be at its 
highest development on the younger pastures. 
Rumex Acetosella. 
Although not recorded on Area 8, this plant had high specific 
frequencies on Areas 6 and 7. On these areas, it was a trouble- 
some weed while the land was under cultivation, but the P.c. fr, 
1 Penmachno, 775 feet. 
