4 THE MONTANA EXPERIMENT STATION. 



collection of the species in a herbarium and from the study of the 

 different plants in the field. Without this data, it is impossible to 

 draw accurate conclusions as to the abundance and utility or 

 harmfulness of any economic group. Although much has now 

 been done at this Station toward securing the necessary collections 

 of the native flora and in the stud}' of the economic conditions of 

 the various parts of the state, any present treatment of a large 

 economic group, like the weeds, must of necessity be very imper- 

 fect, as large and important sections of the state are nearly 

 unknown scientifically and several large agricultural districts have 

 not been visited. 



The study of the weeds of any region must include the sources 

 of infection and the means by which the\r spread over the country 

 when once introduced, as well as the adaptation of native plants 

 to conditions of tillage and habitation and the means to be 

 adopted for their restraint and eradication. The subject is of 

 special interest in a new state like Montana, where the population 

 is relatively scant and the agricultural districts are widely 

 separated from each other and often from direct weed infection 

 from abroad and where the distribution and composition of the 

 native flora is rapidly changing, owing to the increased settlement 

 and effects of grazing immense herds of stock over the unculti- 

 vated portions. It is also desirable to make note of the present 

 status of these weeds in the state in order to observe their future 

 histor}'. Many introduced species are unsuited to our climatic 

 conditions and die out or maintain a precarious existence here, so 

 that they may well be disregarded as a source of danger. Others 

 that appear harmless in the Eastern states may here develop most 

 dangerous habits and require the combined efforts of a community, 

 or even the aid of the state, to check their spread or effect their 

 destruction. It is the object of this paper to present a summary 

 of our present knowledge of the weeds of this state, to indicate 

 the most dangerous introductions and suggest means for their 

 restraint or eradication. It is hoped that farmers, stockmen and 

 others interested, will send this Station specimens of any plant 

 found troublesome or threatening to become a pest in their 

 vicinity, so that the species may be determined, its habits studied 

 and timely warning given to other parts of the state, that prompt 



