i6 



\\ BEDS or FARM LAND 



helps to distribute weeds, as mud containing the seeds is 

 carried about on the feet of stock, cartwheels, boots of human 

 beings, walking sticks, and in various other ways. This is 

 often well shown along cart tracks or round gateways through 

 which much traffic passes, as an assemblage of weeds character- 

 istic of different situations may often be found there. For 

 instance, the trampled mud round a single gate between a 

 public road and a ploughed field on chalky 

 Boulder clay was colonised by l : 



(i) Arable Weeds (from field). Slender 

 foxtail, scarlet pimpernel, charlock, fat hen, 

 dwarf spurge, knotgrass, groundsel, field 

 speedwell. 



{2) Grass-land Plants (from grass by 

 roadside). Ryegrass, cat's-tail, greater 

 plantain, broad-leaved dock, couchgrass. 



(3) Weeds found in both Situations. 

 Silverweed and creeping thistle. 



Traffic over such an area in muddy 

 weather would be a constant means of 

 weed distribution. It can easily be under- 

 stood that mud containing weed seeds may 

 be transported for very long distances 

 when it is carried on the feet of animals 

 or on the boots of men travelling by train 

 or motor. On the whole it is the arable 

 weeds that are chiefly distributed in this 

 way, as roadside weeds usually have more 

 specialised arrangements. The carriage 

 of mud on cartwheels is often responsible 

 for the temporary appearance of arable 

 weeds in grass fields, as such plants as 

 shepherd's purse, swinecress, chamomile, mayweed, spurry, and 

 poppies will all spring up along wheel tracks across grass, 

 though they rarely persist for more than one season unless 

 the grass is obliterated and bare soil conditions prevail. 



The spread of weeds by " damp carriage " is rarely recog- 

 nised, but many seeds will adhere to damp boots or clothing 

 where there is an entire absence of mud. Groundsel, ragwort, 

 hawkbit, daisy, buttercup, dandelion, mouse-ear chickweed, and 

 the seeds of various grasses may all be collected and transferred 



1 Woodruffe Peacock, E. A. (1918), " The Means of Plant Dispersal : Mois- 

 ture and Mud Carriage," Selborne Magazine, XXIX, No. 338, pp. 20-22. 



Fio. 4. SPIKELET OF 

 FRUITS OF WILD 

 OAT (Avena fatua), 

 showing the hairs 

 and the twisted 

 awns. 



