HAMILTON SCIENTIFIC ASSOCIATION. 107 



enumerated as instrumental in diffusing plants over the globe, 

 we have still to consider man — one of the most important of 

 all. He transports with him, into everj' region, the 

 vegetables which he cultivates for his wants, and is the 

 involuntary means of spreading a still greater number which 

 are useless to him or even noxious. 



Plants have been naturalized in seaports by the ballast of 

 ships, and several examples of others which have spread 

 through Europe from botanical gardens, so as to become 

 more common than many indigenous species. 



lyittle more than a century ago a plant of the common 

 flea-bane of this country, Erigeroii Ca?iadense, was introduced 

 into the botanical garden at Paris, and years ago the seeds 

 had been carried by the winds so that it was diffused over 

 France, the British Isles, Italy, Sicily, Holland and Germany. 



The common thorn-apple. Datura Stramonium, now grows 

 as a noxious weed throughout all Europe with the exception 

 of Sweden and Lapland. It came from the East Indies and 

 Abyssinia to Britain, and was thus universally spread by 

 certain quacks who used its seed as an emetic. The same 

 plant is now abundant throughout the greater part of the 

 United States and Canada, along waysides and farm yards. 

 I had occasion to visit Toledo, O., a few years ago, and out- 

 side that large town some vacant lots were literally covered 

 with it. 



The yellow monkey flower, Messiulus Luteus, a plant 

 from the Canadian North-West, has now established itself in 

 various parts of England. A specimen of this plant was sent 

 me a few years ago by a beginner in botany with whom I 

 was exchanging specimens. It was collected in Dorsetshire. 



Some years ago I found a patch of the beautiful plant 

 Lithospermum ajigustifolia growing on the Beach north of the 

 Canal. I submitted the plant to an eminent botanist who 

 was on the expedition which fixed tlie 49th Parallel of 

 Latitude many years ago. He suggested that this plant was 

 characteristic of a part of the continent more than a thousand 

 miles from where I found it, and the conclusion was that the 

 seeds had been carried down from the upper lakes and thrown 



