8 



Ti'iflnnii npi IIS, L. 



J, iti II III II III, Jj. 



Si» intiiii;itt'Iy cnmicctcd in tlicir raiiijo and li:il)its with the 

 exotic plant"* <il' our ticMs and roadsides, an; our native xpccios 

 ill tluur ahnornialiy diU'uMcil Htatcs tliat there seems a propriety 

 in re^V•rrin^' to them here. 'IMu-ir habits an; instruetive as they 

 furnish an exphmation of th«! eircumstanccs whicii have led to 

 the intntchiction of tbrci;iii plants int< the country iti our tiincH. 

 Native species, when they assume these randtlinn' habits — as 

 iu(»st, if j)erliaps not all, (if our doincsticatcMl exotics to a irreater 

 or less extent have in the countries iVom whicii they have come 

 — frcf(uently stra} into <:rain-lields, to roadsides, wharves, and 

 other localities, whence their seeds are readily conveyed to 

 foreiiiU lan<ls, ; lonj^ with ^^rain, wool, packinij;, personal ellccts of 

 emigrants, ballast, and oti r means of transmission, so amply 

 aftorded. Thousands of the seeds thus yearly brouuht to 

 foreiun shores probably never uerminafe, an<l ol' th<»se wlTndi do, 

 perhaps but a small proportion, n^presentiiijj; some of these hardy 

 species, and a i'ew others, which find a conuenial climate and soil, 

 mature and perpetuate their existence. Tlu! n^currini:; immigra- 

 tion, year alter year, of the same as well as occasional other 

 species, soon, however, uives a feature to the vei^etation there. 

 The spreading habits of any of the plants, in the countries from 

 which they iiiivt; come, will have hardened their natures, and lu'rved 

 them iur not only cnduriiij:; the vicissitudes (d', perhaps, dissimilar 

 soils, and a more tryiiiu; elimate, but also of encroachinjjj upon 

 the domains ol' the native vegetation. In tills niaiiner has, [ 

 coneeive, arisen in a larire measure the distribution of the exotic 

 flora of our roadsides and tields. And it furtlier seems un(jues- 

 tionable that those mcmberri of our indigenous flora which have 

 this spreading habit will not oidy be the most likely to mij^rate 

 to and become naturalized in Ibreiiiii lands, but of all species 

 whieh may happen to be .so n.ituralized from here will be the 

 most hardy, and probably have, eventually, the widest ranj^e. 

 Ei'hjriuin C<inti(li'tisr and h\ (iininnm are familiar illustrations. 

 With an extensive range in this country, they have migrated to 

 Europe, whore, in the naturalized state, they now have a wide 

 distribution. (Knoflicrd hicmn's aftords an example of the same 

 feature!. 



Illustrative of this last group there are some well-known plants. 

 R(tHuncuti(s alortlvus, h., is very common on roadsides in difl'erent 



