R. G. Staplbdon and T. J. Jenkin 57 



is frequently seen about waste land near towns, but we have not at 

 present experimented with seed collected from it. It has sometimes 

 proved successful from commercial seeding on fertile soils especially 

 when farmyard manure is freely used. 



Holcus lanatus. This is an indigenous plant on many types of grass- 

 land ; it is presumably a primary plant on the Bridgwater flats in 

 Somersetshire and elsewhere, and it is probably a slight primary plant 

 on some of the more ill-drained types in the districts under review. On 

 poor soils up to the extreme limits of cultivation it rapidly gains on 

 fields especially under meadow conditions, usually reaching its zenith 

 at the third or fourth year and then falUng slightly even if hay is still 

 taken (Table II) ; but it decreases very considerably under grazing. 

 On better soils (or at all events wetter ones) it is still favoured by 

 taking hay, but is more tolerant of constant grazing than on the 

 poorer soils (c/. Table II with Table VIII C and D). It is certainly 

 not a long lived perennial on the poorer soils above about 400', where 

 it gains on the ground by abundant self seeding ; and since it is a universal 

 impurity in the rye grasses^ commonly sown in these districts and can 

 also be carried freely from field to field by the wind, the evidence is 

 against its being even a secondary plant on the types investigated on 

 soils derived from Terannon shales. On the alluvial soils, since it may 

 there long continue under constant grazing, it is probably a secondary 

 or primary plant. Very large sowings of Dactijlis glomerata (10-14 lbs.) 

 would seem to have a decidedly depressing influence on Holcus lanatus 

 even under meadow conditions (see Table VI D). At the College Farm, 

 Aberystwyth on permanent manurial plots for hay (on a field over eight 

 years down) the average percentage yield of Dactylis is 35 %, of Holcus 

 only 4%. 



Bromus mollis et spp. is not so abundant as Holcus on the types 

 investigated, but is probably a truly secondary plant on alluvia and 

 is a slight secondary plant on the poorer soils below 600' ; it may 

 become abundant when the seed is introduced as an impurity. Is 

 essentially a plant of meadow conditions. 



Trifolium hybridum. This exotic, on some soils yields as well in 

 the first hay crop as T. pratense ; but falls off rapidly after the second 



^ 91 % of the samples of perennial rye grass and 78 % of the Italian rye grass 

 samples tested at Aberystwyth in 1913 contained Yorkshire Fog in appreciable amount. 

 Sweepings from the hay loft are still frequently sown. The farmers of the last generation 

 were even more careless than those of the present in their purchase of seed ; consequently 

 the abundance of Fog on certain types of grassland is probably the heritage of negligent 

 farming. 



