EXPERIMENT STATION BrLLETINS. 251 



TABLE III.— NUMBER OF NOXIOUS SEEDS PER POUND WHEN PRESENT TO THE 



AMOUNT OF TWO PER CENT BY WEIGHT. 



Namo of seed. 



Agropyron repens, Quack grass 



Brassica arvensis. Charlock 



Brassica juncea, Indian mustard 



Brassica nigra, Black mustard 



Caraelina sativa, False flax 



Carduus arvensis, Canada thistle 



Cichorium intybus. Chicory 



.Chrysanthemum leucantliemum, Ox-eye Daisy 



Cuscuta sp., Dodder* 



Daucus carota, Wild carrot 



Hieracium aurantiacum, Orange Hawkweed.. . 



Linaria linaria, Butter and Eggs 



Plantago lanceolata, Buckhorn 



Plantago rugelii, Rugel's Plantain 



Silene nocfciflora, Night-flowering Catchfly 



Thlaspi arvense, Penny cress 



Numbers 



in pound 



at 2%. 



2,193 

 4,450 

 0,440 

 5 , !)34 

 4 , .540 



10,878 

 7 , 382 

 32,428 

 12,9.53 

 10,283 



87,300 

 72 , 640 

 n , 209 

 16,509 

 9,080 

 10,771 



iThe species was Cuscuta arvensis, ield.dodder. 



It is thus apparent that without being in violation of tlie law, 

 it w^ould be possible for a sample of seed to contain in one pound up to 

 12,953 seeds of field dodder {Cuscuta arvensis) or 11,209 seeds of 

 buckhorn (Plantago lanceolata) or 87,300 seeds of orange hawkweed 

 {Hieracium aurantiacum) etc. Fortunately such could never be the 

 case in this last mentioned seed owing to its lightness and the ease 

 with which it could be fanned out. Actually, however, samples were 

 collected in 1911 and 1912 that contained 1.5% by weight of clover 

 dodder, i. e. about 20,000 seeds per pound and 10.1% buckhorn i, e. 

 about 56,000 seeds per pound and many samples contained but little 

 less tlian two per cent of the latter. 



Turning now to the different kinds of seeds examined, we find that 

 alfalfa and red (or June) clover (including its various forms such as 

 mammoth and medium clover) made up the majority of the samples 

 analyzed. Alfalfa is a comparatively new crop in Michigan and hence 

 has been the subject of unusual interest on the part of the farmers of 

 the state. This is apparent from the fact that in 1911 and 1912 re- 

 spectively, the samples of alfalfa made up G1.7 and 55.7 per cent of 

 the unofficial samples i. e. those sent in voluntarih^ with red clover 

 which is much more extensivelj^ grown in the state than alfalfa, mak- 

 ing up only 17.2 and 13.6 per cent resi>ectively. Probably the differ- 

 ence is largely due to the fact that the average farmer grows his own 

 red clover seed and so does not usually think it worth while to have 

 it tested, while with a new crop like alfalfa, with unknown seeds and 

 from dealers whose reliability is unknown, he feels the need of having 

 the seed examined. 



In Table IV is shown by numbers and per cent, the distribution of 

 seeds of the sixteen kinds of noxious weeds in the samples of alfalfa, 

 alsike clover, red clover, white clover, timothy, w-inter vetch, lawTi 

 mixtures and all others, in the official and unofficial samples of 1911 

 and 1912. Table V shows similarly the distribution in the same kinds 

 of commercial seed of all the recognized kinds of weed seeds found 

 in them aside from the sixteen kinds of noxious weeds. 



