1915] 



WILLE — FLORA OF NORWAY 99 



orientalis (1812), Campanula patula (1870), Cerastium arv- 

 ense (1817), Chrysanthemum segetum (1704), Cotula coron- 

 opifolia (1875), Conringia orientalis (1859), Erigeron can- 

 adensis (1874), Galinsoga parvi flora (1880), Lepidium per- 

 foliatum (1875), L. virginicum (1889), Matricaria discoidea 

 (1850), Rudbeckia hirta (1880), Senecio viscosus (1804-1808), 

 Thlaspi alpestre (1874), and Xanthium spinosum (1872). 

 Some of these plants are now among the most troublesome 

 weeds in large and small areas in Norway. 



There can, I suppose, be no doubt that man, directly and 

 indirectly, in the 7,000 years in which he has lived in Norway 

 and maintained a lively intercourse — especially during the 

 last 2,000 years — with the rest of Europe, must have assisted 

 in introducing a great number of plants in addition to the 

 above named. Among the former may be mentioned Agros- 

 temma Githago, Anchusa arvensis, A7ithemis arvensis, Avena 

 fatua, Brassica campestris, B. nigra, Bromus secalinus, Car- 

 duus crispus, Centaurea cyanus, Chenopodium capitatum, 

 C. hybridum, C. glaucum, C. polyspermum, C. rubrum, 

 Circium arvense, Convolvidus arvensis, Euphorbia Helio- 

 scopia, E. Peplus, Fagopyrum tataricum, Fumaria officinalis, 

 Galeopsis angustifolia, G. Ladanum, G. speciosa, Galium 

 Aparine, G. Mollugo, Lolium temulentum, Matricaria Cham- 

 omilla, Raphanus Raphanistrum, Sinapis alba, S. arvensis, 

 Sonchus asper, S. oleraceus, Spergula arvensis, Spergula 

 vernalis, Thlaspi arvensis, etc. In addition to these there 

 are a great many species that are generally classed in the 

 floras under the heading "run wild" or " perhaps originally 

 run wild, ' ' and concerning which it may certainly be assumed 

 that they have been introduced by man's mediation in some 

 way or other. 



It is no longer possible to maintain the old dogma which 

 held that the entire plant community migrated step by step, 

 like a regiment of soldiers, and took possession of the country 

 under climatic conditions that were favorable to the various 

 species, while the previous vegetation was decimated and only 

 survived in especially favorable localities; for vegetable 



