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ent upon the commercial relations with foreign countries and the 

 new climatic conditions surrounding them. 



Many of our naturalized and adventive plants have been intro- 

 duced through importation, and some of them date back to a very 

 early period in our history. 



John Josselyn, an English gentleman who visited this country 

 previous to 1672, gives a list of over thirty species of introduced 

 plants which included such well-known forms as the dandelion, 

 shepherd's-purse, pigweed, couch-grass, burdock, sow-thistle, sting- 

 ing nettle, plantain, wormwood, chickweed, may-weed and purs- 

 lane, which were grown in Massachusetts at that time, and Dr. 

 Cutler of Salem left much valuable data concerning our introduced 

 plants in his botanical notes, prepared previous to this century. 



The writings of these early observers are of great value to botan- 

 ists of the present day as some idea can be obtained as to the 

 adaptability of the European plants. From this list of Josselyn's 

 it will be noticed that all of these plants are common enough to-day ; 

 especially is this true in regard to dandelion, shepherd's-purse, 

 chickweed and purslane, the latter plant being formerly grown in 

 the garden and used for greens. 



These plants found in our gardens their proper habitat, and as 

 the cultivated areas were extended they multiplied very rapidly, 

 until to-day they constitute the most extensive weed-growth 

 we have to contend with. The other plants named by Josselyn, 

 although constituting something of a nuisance, are not so abundant 

 because the proper conditions for their thriving were not ob- 

 tained. 



But in order to take into consideration all of our weeds we must 

 pay some attention to those which have been more recently intro- 

 duced. The total number of naturalized plants from other 

 countries which have been established in Massachusetts, and do 

 now propagate themselves spontaneously, is probably about two 

 hundred and fifty ; and the total number of adventive species, or 

 those which have grown one or more seasons but have not become 

 established in our climate, is not far from three hundred. 



While these adventive plants occur now and then on rubbish 

 heaps, especially near manufacturing establishments and along 

 railroads, we cannot say when any of them may take a start and 

 in the course of a few years become as abundant and as much of a 

 nuisance as the white daisy or wild carrot. Indeed, we know so 

 little about the habits of some of these plants that we cannot tell 

 what they are capable of doing in our climate. We already know 

 that among some of the earlier introduced plants some spread only 

 slightly ; for example, coltsfoot was found in Massachusetts as 



