WEEDS OF MONTANA. 



25 



I. ACHILLEA niLLEFOLIUM L. Wild Tansy; Milfoil. 



A perennial plant about two feet high with finely divided 

 leaves and white flowers in a level-topped cluster. Frequent in 

 pastures and meadows, where its bitter herbage makes it dis- 

 tasteful to stock. 



2. AGROSTEMMA GITHAGO, L. Corn Cockle. 



A purple-flowered annual occasional in grain fields, but hardly 

 troublesome here, as it is in the East. Noted in but few localities. 

 It has narrow leaves and fewer and more scattered flowers than is 

 the case with the ordinary cockle (Saponaria Vaccaria) and is 

 silky hairy throughout. 



3. ALLIONIANYCTAGINEA,Michx. 



A tall (2 to 4 feet high), smooth, 

 much-branched perennial with heart- 

 shaped opposite leaves and clustered 

 purplish flowers. Occurs as a weed in 

 gardens in the extreme eastern part 

 of the state (Calais and W T ibaux) and 

 promises to spread westward. 



4. AHARANTHUS ALBUS, L. 



Tumble-weed. 



A widely-spreading annual weed, 

 common in loose or cultivated 

 ground. It begins blooming in early 

 spring and produces seed all the seas- 

 on. It is killed down by the first 

 heavy frost and the large globular 

 mass breaks off from the root and is 

 driven about by the wind, scattering 

 its seeds throughout its course. Ap- 

 parently native east of the Divide. 

 Hybridizes with the next. [Fig. 1]. 



Fig. 1. Amaranthus albus, L. 

 Branch V2 natural size. 



