INDIVIDUAL SPECIES. 43 
Stapledon in his list of arable land weeds (17), and Brenchley 
shows that its seeds rarely lie dormant except in the soils of very 
old grass land (3). It was not recorded by the present writer on 
an oat stubble, and the following results obtained on well cleaned 
land’ at 50 feet also show that the plant may not occur where not 
SOWN :— 
Seed sown in lb. per acre: o ¥% Yy % 
Sp. fr. at 1} years: ° 9 23 27 
eo 2 wt © 145 335 35 
On the other hand, the following results obtained on 
imperfectly cleaned land,? show that it may occur in some quantity 
even in young pastures, and that in some such cases the inclusion 
of seed in the seeds-mixture may have no appreciable effect :— 
Seed sown in lb. per acre: nil yy 
Sp. fr. at rd years: 6 4 
i Sp ES ay 2 8 
we cg 2 4s 8 
On the whole, these results tend to show that the plant does 
not usually persist through a period of cultivation which includes a 
cleaning crop, but that where the land is imperfectly cleaned, 
especially at relatively high elevations, it may persist by some 
means. Its obvious success, at least in some cases, when sown 
on well-cleaned land, shows that although it may not appear 
spontaneously in the young pasture, the conditions in those cases 
are not such as to inhibit its growth. 
In view of this, the results for Apeas 1-8 are especially inter- 
esting. The plant had a Sp. fr. of ro on the old grass-heath 
(Area 8), but it was not recorded on Area 7 at 44 years, nor on Area 
6 at 54 years. In this case, therefore, it had been completely 
1 These are average results for four plots each over three acresin extent, 
and six plots each a fourth of an acre in extent, all in the same field, at the 
College Farm, Aber, Bangor. 
2Penmachno, 775 feet, The two areas are the two halves of the same 
field, 
