58 



THE MONTANA EXPERIMENT STATION. 



112. SISYMBRIUM ALTISSIMUM, L. Tumbling Mustard. 



A European annual of 

 the mustard famih', two 

 or three feet high, with 

 upper leaves narrow or 

 finely divided and the 

 lower broader-lobed, and 

 having a widely branch- 

 ing, level-topped spread 

 of yellowish flowers and 

 slender fruit pods two 

 or three inches long. This 

 has been found to be a 

 most pernicious weed in 

 Canada north of this 

 state and is extending 

 southward. Specimens 

 have been collected at 

 Great Falls, Helena, Cen- 

 tral Park and Belgrade, 

 and it is fairly taking the 

 grain fields in some parts 

 of the Bitter Root and 

 Flathead valleys. It 

 should not be allowed to 

 secure a footing in any 

 agricultural section, as 

 its enormous fertility, 

 tumbling habit, and special adaptation to our climate will 

 probably make it far more dangerous to the farmer than any of 

 the weeds already outlawed in the state. [Figs. 17 a and b.] 



Fig. 17a. 



Sisymbrium altissimum, L. 

 Vs\ b and c natural size. 



and d 



113. 



Tansy Mustard. 



SISYMBRIUM INCISUM. Engelm. 



A slender annual of the mustard family, one to three feet high, 

 having small, yellow flowers, short spreading pods and finely 

 divided leaves. Common along roadsides, in grain fields and 

 waste places. Has the appearance of a native in some parts of 



