124 THE JOURNAL OF BOTANY 



having been sprinkled plentifully with the seeds. It is evident 

 that, in this manner, wind-distributed seeds would be much better 

 able to introduce themselves into new districts, and when once 

 introduced would rapidly spread. 



The number of forage plants in the above lists varies very 

 widely. If we exclude the Clerkenwell site, upon which much 

 vegetation had evidently been destroyed, the number of species 

 may be said to be roughly proportional to the area of the site. 

 The smaller sites visited are in somewhat crowded situations, and 

 a comparison of the lists will strengthen the suggestion that the 

 number of species found corresponds with the space afforded for 

 horses to stand during the time that the site was being cleared 

 and levelled. In the case of the Upper Thames Street wharf, and 

 possibly some of the other sites, the few^ plants of the kind in- 

 cluded in this group may have been due to rough packing material 

 derived from the same source as rough forage. 



Attention has already been called to the interesting variety of 

 garden escapes found upon the Bloomsbury site, suggesting the 

 probability of a residence upon the site having been occupied by 

 a botanist interested in economic plants. Of the garden escapes 

 found upon these sites only Baphanus sativus and Ficus Carica 

 occurred upon more than one site, thus showing that plants 

 belonging to this group were either intentionally introduced on 

 each site by man or were derived from the scattering of kitchen 

 stuff. 



The plants likely to have been introduced by birds are few in 

 number, and were absent from some of the sites. It is evident 

 that this means of plant distribution is not effective in large 

 towns. Probably the few birds which reach the centre of our 

 large towns would have deposited their seeds before reaching the 

 heart of the city. 



It is worthy of note that a total of seventy-eight species were 

 found upon these five sites. A surprising result when we con- 

 sider the situation of the sites and the brief period which inter- 

 venes between the clearing of a site and the erection of new 

 buildings. 



The five centres visited afford scarcely sufficient data to justify 

 dogmatic conclusions as to the means by which plants are carried 

 into the centres of large cities, but a comparison of these five 

 sites points clearly to a common origin for most of the groups of 

 plants discovered, and suggests their distribution in the manner 

 described. 



I must thank Mr. A. E. 0. Stutfield, Steward of the Bedford 

 Estate, and Mr. Mark M. Merriman, clerk to the Dyers' Company, 

 for affording facilities for visiting sites, and members of the staff 

 of the National Herbarium for assistance in naming plants. 

 Thanks are also due to Mr. Miller Christy and to Mr. E. Bidwell 

 for kind assistance. 



