53 



What kind of seeds must be given as weeds in the reports of the testing 

 stations ? 



To enable this question to be answered, Mr. Dorph-Petersen initiated 

 an enquiry by sending to the various European and American stations a 

 questionnaire including the names of 206 wild plants, belonging to 

 40 families, requesting them to strike out those not met with at each 

 station, to add those not named, underlining the noxious plants and to 

 number the species 1-5, No. 1 to include the most frequent kinds. 



Thirty stations returned the questionnaire duly annotated. 



These stations, in their replies, added species peculiar to their 

 regions, so that, besides the elucidation of the question of weeds, we have 

 information as to the determination of the origin of seeds. 



From the reports sent in, it can be seen that very few kinds of weeds 

 are to be met with equally frequently at the different points of the temperate 

 zone, which is, for us, the most important one. 



The following species were most frequently and abundantly found in 

 North and Central Europe (including S. France and N. Italy) and even in 

 America : — 



Sinapis arvensis 



Chenopodium album. 



Plantago laneeolata 



Rumex acetosella. 

 Specially in Europe, but less uniformly : — 



Daucus carota. 



Sherardia arvensis. 



Centaurea oyaniis. 



Stellaria media. 



Brunella vulgaris. 

 sttid variable in different countries : — 



Ranunculus. 



Vicia. 



Galium. 



It would, therefore, appear that these weeds should always be named in 

 the reports, and perhaps their quantities given also. 



As for the other species, even when a more restricted geographical area 

 is in question, there are such great discrepancies in their respective frequency 

 that it would be impossible to require all stations to include them in their 

 reports. But, nevertheless, such weeds may have special importance for 

 some one region or other, and it would be requisite in such cases, in the 

 interest of the growers, to name these weeds in the reports. For example, 

 the large-seeded Dodder, so unimportant for Northern lands and so noxious 

 for leguminous forage plants in Central and Southern Europe. 



Is it possible to state precisely what categories of weed seeds should be 

 pointed out by the testing stations ? 



Every country with a distinct climate has its own noxious plants. 

 Their propagation can only be avoided if the grower is made aware, by 

 analysis, of their presence in the seed to be employed. In France, Bromus 

 mollis in Gramineae and Melilotus officinalis among leguminous seeds must 

 always be notified. 



The names of certain weeds which are specially prescribed are given in 

 some Acts, as in the regulations attached to the U.S. Seed Importation 

 Act of August 24th, 1912, where 105 species are given. 



In the explanatory regulations of the Canadian Seed Act of 1923, four 

 categories of extraneous plants are grouped as imder : — 



(1) Primary noxious weeds - - - - - 8 species. 



(2) Secondairy noxious weeds 22 „ 



(3) Useless weeds - 8 ,, 



(4) Harmful weeds, include all species not named above. 



These species clearly specially concern Canada, The national stations, 

 and perhaps foreign ones, mi:^t pay them the greatest attention. 



