58 MINNESOTA WEEDS 



Description. — Shepherd's purse belongs to the mustard family. 

 It is generally an annual, but is sometimes a winter annual. It has 

 been found in flower as early as March. The large leaves, which are 

 more or less notched, form a rosette at the base of the plant. The 

 smaller leaves are arrow-shaped. The plant varies from six to twenty 

 inches in height. It has small white flowers. The seed pod is tri- 

 angular in shape and about a quarter of an inch in diameter. The 

 name, shepherd's purse, is derived from the shape of the seed .pod. 

 The reddish yellow seeds are so small that a single plant often pro- 

 duces 50,000 of them. They are found in clover and grass seed, 

 particularly in lawn grass mixtures. The plant flowers and matures 

 seed throughout the season. It is found in waste places, orchards, 

 and gardens, and grows in all kinds of soil and in nearly every part 

 of the State. 



Eradication. — Shepherd's purse is troublesome mainly because 

 of its early and prolific seed-bearing qualities. It is easily subdued 

 by. good plowing and clean culture It yields readily to the culti- 

 vator and hoe and may be held in check by any good arrangement 

 of crops in rotation. It often gains a foothold where bare spots 

 have been left in grain fields or at roadsides or in thin meadows and 

 pastures. Well-prepared seed beds and full seeding will prevent the 

 appearance of the weed in most cases. 



Wild Mustard (Brassica arvensis L.) 



Other common names. — Charlock, field kale, corn kale, corn 

 mustard. 



Description. — Wild mustard is so common that a description is 

 hardly necessary. It is an annual weed which grows from one to 

 three feet high. It is covered with short stiff hairs, and is often much 

 branched. The flowers are bright yellow and quite conspicuous. 

 The podlike fruit is generally about one and one-half inches long. 

 When the seeds are mature, the pod opens and discharges them. 

 The seeds are round and comparatively smooth; the size is somewhat 

 variable, and the color cither black or reddish brown. As the seed 

 contains a large percentage of oil, it will lie in the ground for a long 

 time without losing its germinating power They have been known 

 to lie dormant for fifteen years and then germinate. They are found 

 in all cereals and are common in red clover. They are easily sepa- 

 rated from cereals, but not from clover as they are about the same 

 size as clover seed. 



Eradication. — Wild mustard is one of the most troublesome weeds 

 because of its persistent seeding habit and the endurance of the seeds 

 when buried in the soil. It is most common in fields that are devoted 



