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from old gardens ; others have got about from having been 

 themselves formerly cultivated as crops. Garden species, some 

 now out of date, but others still kept up for their beauty, or 

 scent, or culinary uses, or supposed medical properties, that have 

 run wild are very numerous. 



Again some species are known to have been planted in the 

 spots in which they are now met with. Such, I believe, has been 

 the case with the sweet-smelling flag (Acorns calamus) growing 

 freely on the banks of the Avon in two or three places. 



Several trees and shrubs have in like manner been probably 

 planted by the hand of man originally, though they may have 

 since spread of themselves in some instances. Such are the 

 Lime, Maple, Box, and the Berberry, this last being often cultivated 

 for its fruit. 



To such causes we may add the introduction of new plants by 

 ballast. A considerable number of foreign species have found 

 their way to our shores in this manner, and are now frequent in 

 places, especially about sea-port towns. 



It has been thought, and not without reason, that the SeneUera 

 d'uhjma, which grows in some plenty under walls by the side of 

 the Avon, between Norfolk Crescent and the Gas Works, was 

 originally brought with ballast into the neighbourhood of Bath. 



Occasionally accident brings plants to this country from much 

 further distances even than the Continent. As an instance in 

 point, we may mention the Elodea canadensis, imported from 

 Canada, nobody knows how, first observed in the north of 

 England and Scotland in 1847, but now so abundant as to prove 

 one of the greatest pests, choking up our rivers and canals to 

 such a degree as to impede navigation. During the summer 

 months our own canal at Bath is full of it in many places, 

 almost to the exclusion of other weeds. 



Thus we see how many causes are at work, chiefly through the 

 agency of man, to swell the number of plants growing in a 

 particular district, as also to leave us in doubt what exact 



