CRUCIFERAE MUSTARD FAMILY 
WILD MUSTARD. CHARLOCK 
Brassica arvensis (L.) Ktze. 
The Wild Mustard or Charlock was introduced into this 
country from Europe, has flourished and has become a very 
common weed. It occurs in grain fields and waste places through- 
out the United States. | 
E It is an annual, 1-2 feet high and 
branching above the middle, some- 
times covered with stiff scattered 
hairs but sometimes entirely smooth. 
The leaves are rough to the touch, 
coarsely and prominently ribbed and 
veined, and with edges irregularly 
notched or wavy. 
The yellow flowers, blooming 
from May to November, have the 
usual structure for members of this 
family and the pods are commonly 
smooth but rather knotty. 
The Black Mustard, Brassica nigra 
(L.) Koch, is another European plant 
that has become a weed here. It is 
larger, growing 2-7 feet tall and branch- 
ing freely. Its flowers are smaller and 
its pods are shorter and usually closely 
appressed to the stem. It blooms from 
June to November and is found in 
fields, along roadsides and in waste 
places throughout the country. Table 
mustard and mustard oil are made 
from the seeds of this plant and in 
Europe it is extensively cultivated 
for the purpose. It may also be cultivated for fodder, in which case 
it is harvested before the seeds mature. 
The White Mustard, Brassica alba (L.) Boiss., also from Europe 
and cultivated, may be distinguished from the similar Charlock, 
Black Mustard and Rutabaga by the fact that all its leaves are pale, 
deeply divided and do not clasp the stem. The pods are bristly and 
have large 1-seeded angular beaks that are sword shaped and one- 
half the length of the whole pod. 
There is a flower, a little flower 
With silver crest and golden eye, 
That welcomes every changing hour, 
And weathers every sky. 
A Field Flower—JAMES MONTGOMERY 
127 
