MUSTARD FAMILY 



CRUCIFERAE 



TUMBLE MUSTARD 



Sisymbrium altissimum L. 



The Tumble Mustard is another immigrant from Europe 

 which has spread over the continent, north from Virginia, 

 Missouri, and Utah into Nova Scotia, Ontario and British 



Columbia. In many places 

 it has become a very annoy- 

 ing weed. 



This is a biennial which 

 in the first year produces a 

 rosette of leaves but no up- 

 right stem. The food manu- 

 factured by the leaves is 

 stored in the root, from 

 which the plant sends in the 

 second year a smooth, erect 

 and freely branching stem 

 2-4 feet high, on which 

 flowers and seeds are pro- 

 duced all summer. The 

 leaves vary greatly from 

 the base to the top of the 

 plant, all gradations be- 

 tween the kinds shown 

 being found. 



The small, pale yellow flowers have the typical struc- 

 ture of flowers of this family. The pods are very slender and 

 divided longitudinally into 2 parts, each of which contains i or 

 2 rows of seeds. Sometimes an upper portion of the plant breaks 

 off and is blown along over the ground, or it may get caught on a 

 Tumbleweed or a Russian Thistle which is being blown about. 

 In this way the seeds are threshed out of the pods and scattered 

 over the soil. 



The Hedge Mustard, Sisymbrium officinale (L.) Scop., is a 

 common weed throughout Illinois. It is erect, 1-3 teet high, smooth 

 or somewhat soft hairy, and its spreading branches are rigid. The 

 flowers are deeper .yellow and much smaller; the thick-walled pods 

 are hairy, short stalked and appressed to the scarcely branched 

 stem. The valves have a strong prominent midrib. It is likewise a 

 European invader of waste ground. 



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