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SPONTANEOUS EXOTICS. 



By James Bettten. 



In the neighbourhood of London, and other great cities, especially 

 such as are seaport towns, a class of plants occurs which is distinguished 

 by the name of " ballast plants," and setting aside such species as the 

 Groundsel, &c., which are almost ubiquitous, many of our reputed British 

 species are almost entirely confined to such localities, Melilotus vulgaris, 

 for example, has a most remarkable predilection for these spots, and this 

 is also the case with Datura Stramonium^ and many more. But besides 

 these two divisions of the class there is yet another which I think I may 

 call the most interesting of the three, comprising such plants as are 

 certainly foreign to this country, but which appear spontaneously, and can 

 scarcely be reckoned as garden escapes. -i' Many of these have now become 

 completely naturalised in one or two localities ; others are imperfectly 

 established ; while some only appear occasionally, and do not retain their 

 position with us. Now although it may be generally felt that these w^an- 

 derers have not the interest for a British botanist that plants indigenous 

 to his country enjoy ; yet it must be conceded that they are at least worthy 

 of some attention, and should not be passed by without notice. It is 

 impossible to draw correctly the line which separates our native plants 

 from introduced species ; and all attempts to do so have proved, and will 

 prove, more or less abortive. The learned author of the Cijhele Britannica 

 doubts the true British nativity of the Violet, except in the Isle of Wight ; 

 and each person has his own list of " excluded species," either larger or 

 smaller than that of the London Catalogue, for but few agree on the subject. 

 As a resident in London, where true British botany is, to a certain extent, 

 out of the question, I have given considerable attention to the class of 

 plants alluded to, and have been at some pains to collect as perfect a list 

 of them as possible from various botanical works. The Phytologist, both 

 the old and new series, is a perfect treasury of information on this branch, 



* Of course, I do not mean to assert, by the term *• spontaneous," that the 

 appearance of these species is untraceable to the ordinary metliod of plant dispersion, 

 by seed: but I use the word to imply only, that as far as the direct agency of man 

 is concerned, they have sprung up of their own accord. 



No. 12, Oct. 15. N 



