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 1 or 
2 rows of seeds. Sometimes an upper portion of the plant breaks 
off and 1s 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 feet 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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