Winifred E. Brexchley 27 



A certain number of weeds appeared that are common to arable and 

 grass land, but they are evidently present here in their character of 

 arable weeds. The true grassland plants were represented by one solitary 

 species. TrifoUiim pralense, of which only two plants appeared. Few 

 grasses occurred except for a number of Agrostis sp. which is a typical 

 arable weed and should really be included in the list of arable seedlings, 

 raising the grand total to 782 + 43 = 82.5. 



(2) Barn Field (8-0). 



Barn Field has carried root crops year after year for 61 years since 

 1850, and the plot 8-0 has received no manure of any kind during the 

 whole period. As a result of this treatment the soil is now much impover- 

 ished and supports only a feeble type of vegetation, and in addition the 

 continual hoeing and cultivating has reduced the weeds to a minimum, 

 as few of them have any opportunity of forming seed before they are 

 hoed up. This is well shown by the results obtained from the soil samples. 

 Two holes were sampled, maicing up 24 pans. During the whole IC 

 months of the experiments only eight pans produced any seedlings, and 

 three out of the eight were occupied solely by Senecio vulgaris, a possible 

 intruder. Senecio vulgaris occurs rather frequently on Barn Field, and as 

 most of the seedlings appeared in the pans during the first three months 

 of the experiment it is quite likely that the seeds were really associated 

 with the soil and were introduced with it, so that in this case they would 

 not be intruders. Altogether seven arable seedlings and three arable or 

 grassland plants appeared, the grand total of 20 seedlings from an area 

 of |- sq. foot of soil being made up by 10 Senecio vulgaris seedlings. 

 Every seedling appeared within the top six inches of soil, and further- 

 more, all the seedlings made ver}- feeble growth, showing that the seeds 

 were weak. The paucity in the number of species of arable weed seeds is 

 probably more due to the continual cultivation for roots than to the 

 starved condition of the soil, as even on the heavily manured plots in the 

 same field only nine or 10 species of weeds occur, and these are present 

 in very small quantity. 



(3) Agdell Field (5). 



This plot has been left unmanured since 1848 and has been worked 

 under four course rotation experiments during the period of 69 years. 

 In the third year of each course the plot has been left fallow, so that 

 specially good opportunities have arisen of cleaning the land, as the 

 seedlings that germinate during the fallow time are to a large extent 



