VITALITY OF WEED SEEDS 77 



quiry often shows that this old pasture has been under arable 

 cultivation at some time or other, thus accounting for the 

 presence of arable weed seeds. Nevertheless, there are many 

 puzzling cases in which no history of arable cultivation can be 

 traced. Where this occurs at a distance from other arable 

 fields, as sometimes happens when moors are reclaimed, it 

 seems that of necessity the seeds must be carried to the spot 

 on a large scale by some means of transport hitherto undetected. 

 As a general rule, however, the presence of seeds buried in 

 the soil is sufficient to account for the large weed crops. By 

 experiment and observation much information has been 

 gathered as to the ability of various weed seeds to withstand 

 burial, but even yet our knowledge of the matter is very 

 incomplete, both as regards the species concerned and the 

 means by which the seeds adapt themselves to the conditions 

 of burial. 



A striking characteristic of the majority of farm weeds is 

 the abundance of seed that is produced. Only a very small 

 proportion of this seed finds itself immediately under conditions 

 suitable for germination, and the greater number of seeds are 

 compelled to remain dormant or else to perish. These wait- 

 ing seeds do not all remain on the surface of the ground, 

 large numbers being carried underground by various agencies. 

 Some of these agencies are well known, but others are easily 

 overlooked. The various means of burial have been summed 

 up by Woodruffe Peacock from his own observation as 

 follows : 1 



(1) Means Influenced by the Activity of Human Beings and 

 Domestic Animals. Spade, plough, and foot pressure by stock. 

 Cattle drive seeds in 5 inches, horses 3 inches, sheep 2 inches 

 or more, while wheel ruts carry seeds down IO inches in some 

 cases. 



(2) Environmental Means. 



(a) Wind, including local whirlwinds and storm columns. 



() Water, which, however, usually destroys fertility. 



(f) Mammals, as fox, rabbit, squirrel, polecat, Norway rat, 



mole, water vole, stoat, weasel, badger, long-tailed 



field mouse. 

 (</) Birds. 

 (*) Insects, as ants, burrowing insects, larvae. 



1 1 am indebted to the Rev. E. A. Woodruffe Peacock for the loan of 

 unpublished MSS. containing this information. 



