8 Buried Weed Seeds 



sampled consist of good soil, and not of cla}'. A large number of grass 

 and Luzula (species, probably = campestris) seedlings appeared in the 

 top inches of soil and grass seedlings were also abundant in the second 

 and third inches, but below this depth very few seeds germinated, 

 except that in one hole a considerable number of grasses appeared seven 

 inches down about a year after the beginning of experiment. Isolated 

 grass seedlings occurred down to the ninth inch, probably derived from 

 seeds that had been washed through the crannies or carried down by 

 worms. During the 14 months of the experiment only 10 other seedlings 

 appeared, inclusive of all species, with the exception of a few suspected 

 groundsel and sowthistle plants. Eight of these were typical grassland 

 plants, but the Alniilex or Chenopodium in the second inch and the 

 Polygonum avicidare in the eighth inch were probably derived from seeds 

 carried by birds or stock, as sheep and cattle have free run of the com- 

 mon. It is rather surprising that so few species occurred other than 

 grasses and woodrush, but this may be due to the fact that the grazing is 

 so close that only a very small proportion of plants have any chance to 

 ripen and shed their seeds. The grasses that appeared were varied, but 

 the greater number consisted of species of Agrostis, especially below the 

 top inch of soil. Clovers were conspicuous by their absence, although 

 plent}' of leguminous plants occur on the Common. This is again attri- 

 buted to the failure of the plants to form seed except in isolated cases. 



(2) Park Grass. 



There is no evidence available of this land being ploughed, and it is 

 quite certain that it has been imder grass for at least 300 years. The soil 

 is fairly heavy and carries a good natural herbage, which has been 

 allowed to develop undisturbed by stock for 40 years or more. Hay is 

 cut every year, but as many of the plants have the opportunity of ripen- 

 ing their seeds one would naturally expect a much greater variety of 

 species than was obtained from the close cropped Common soil. The 

 difference proved to be most striking, for, apart from grasses, leguminous 

 plants and possible intruders, 353 seedlings appeared between April, 

 1916, and August, 1917, compared with less than 20 from the Common 

 soil. Practically all these were typical grassland plants^, and the greater 

 number occurred in the top six inches of soil. The maximum yield of 

 seedhngs was obtained from the second inch, and the number steadily 



1 Centaurea nigra, Cerastium i-ulgatum, Ranunadus sp. and Sfellaria media have been 

 separated out in the other tables as arable or grassland plants, but here they are so 

 obviously present in their capacity of grassland plants that no division has been made in 

 Table II. 



