456 NATURALIZED PLANTS OF GREAT BRITAIN. [June, 



our old writers, nor is it certainly indigenous on the neighbour- 

 ing parts of the Continent. 



Several of these, being found near houses, on walls and rub- 

 bish-heaps, and by roadsides, are very liable to be carried acci- 

 dentally, or mixed with agricultural seeds. 



It will be remarked that out of the 83 species which are here 

 treated as thoroughly naturalized iu Great Britain, no less than 

 27 are considered indigenous by some one or more of the Eng- 

 lish authorities ; five in particular that are universally admitted 

 by our writers deserve separate mention : — 



Senebiera didyma. Kumex pulcher. 



G-eranium pyreuaicum. 1 " Denizens," Mercurialis annua. 

 Pyrefcki'um Partheuium. J Cybele Britannica. 



The introduction of all our naturalized plants is ascribed to 

 the agency of man ; the influence of winds, currents, or birds is 

 extremely doubtful, and only admitted as barely possible in one 

 instance, that of Ononis reclinata, the sole representative of the 

 Leguminosce, a family whose seeds above all others are able to 

 resist the action of salt-water. 



The absence from the list, of such plants as grow in saline 

 situations on the coast, is worthy of attention, and seems to dis- 

 prove any recent transport by marine currents ; and in the same 

 way the pappus of the Composite and Valerianacece, on which so 

 much stress is usually laid, has not greatly raised their number 

 above the proportion found among the indigenous plants. Still 

 less is thought of the influence of birds in carrying seeds to any 

 distance, or across an arm of the sea ; thus the hypothesis that 

 the seeds of Cotoneaster vulgaris were deposited on the Orme's 

 Head by some redwing or fieldfare migrating from Norway, is 

 dismissed as highly improbable. 



There are but very few cases where seeds appear to have been 

 carried on the clothes, or attached to bales of merchandise, or 

 with ballast ; the great majority of our introduced plants, Eu- 

 ropean as well as American, have become disseminated through 

 cultivation in gardens, or trafiic in agricultural seeds; and it is 

 remarked, in support of this view, that most of the naturalized 

 species occur in the south of England, which is more thickly in- 

 habited, and where gardens are more general, though allowance 

 must be made for its more favourable climate. On the other 



