MICHIGAN ACADEMY OF SCIENCE. 33 



THE RAPID EXTENSION OF WEEDS IN MICHIGAN. 



W. J. Beal. 



In volume five of the Michigan Academy of Science, may be foiintl an 

 approximately correct list of weeds indigenous to Michigan. This list 

 consists of about thirty-five species only. The same report contains a list 

 of seventy-eight species of weeds introduced from Europe and Asia. 



For use in the laboratory, I have a list of two hundred and six species of 

 weeds to be found thriving in this state, and I feel sure that if this state was 

 thoroughly searched, fifty or more additional ones would be found, and where 

 the limit will eventually be, I dare not predict. 



HOW^ ARE WEEDS INTRODUCED AND HOW^ ARE THEY SPREAD? 



1. By hve stock, carried in the hair or fleece or carried by the feet; 

 in some instances -passing alive with the excrement. 



2. By unground feed stuff purchased. 



3. By adhering to the insides of sacks where they were placed with 

 grain. 



4. In barnyard manure drawn from town. 



5. In the packing of trees, 'crockery, baled hay and straw. 



6. By wagons, sleighs, threshing machines. 



7. Sometimes by plows, cultivators and harrows. 



8. By railway trains passing near a farm. 



9. By ballast of boats at wharves. 



10. By wool-waste at factories. 



11. By birds, squirrels, and mice. 



12. By water of lirooks, rivers, by washing and Ijy irrigating ditches. 



13. By the wind aided ])y little wings and by drifting on the snow. 



14. By dropping seed to the ground from extending branches and re- 

 ])eating the process. 



15. By creeping rootstocks, as ,Iune grass, quack grass and toad-flax. 



16. By piercing potatotes, carrots, etc. Quack grass, June grass, Bermuda 

 grass are sometimes carried to other fields or farms where the tubers and 

 roots are planted. 



17. As every kind of weed goes onto a farm to stay there, it follows that 

 as a country becomes older the greater the number of kinds of weeds. As 

 a rule, each farm is annually getting more sorts of weeds, and as each farmer 

 is cultivating weeds, they are more freely distri])uted in every field and along 

 every roadside, and l)y exchanging seeds, they are carried to neighboring 

 farms. 



A great many farmers buy and sow whatever the merchant offers them 

 under the name mentioned. For examj^le, I have a sample of something 

 called clover seed, sold })y a dealer in this state. It contains about 40% 

 of narrow-leaved plantain, which I consider one of the worst of clover weeds. 

 A large majority of weeds hail from older countries, more especially from 

 Europe. 



There are a few weeds, like Canada thistle and qmu-k grass, that may 

 infest any crop of farm or garden, but in most cases, whether to call a weed 



