CRUCIFER.^— MUSTARD FAMILY 



BLACK MUSTARD 



Brdssica nigra 



Annual. A large, branching plant bearing many 

 yellow crucifer flowers, common in fields, roadsides, and 

 waste places. A well-known weed in California. Natural- 

 ized from Europe. June-November. 



Stem. — Two to seven feet high, branching widely. 



Leaves. — Alternate, petioled, large, coarse, rough, dark 

 green. Lower leaves are eight to twelve inches long and 

 consist of a central midrib which bears two or three 

 pairs of small irregular divisions and a large terminal 

 lobe which is very irregularly lobed and toothed. The 

 upper leaves are less divided and the uppermost are linear, 

 entire, and commonly drooping. 



Flowers. — Yellow crucifers, in long, dense racemes, 

 both terminal and lateral. 



Sepals. — Four, pale yellow, narrow, widely spreading. 



Petals. — Four, with long claw and spreading blade. 



Stamens. — Six, four long and two short. 



Pistil. — Ovary two-celled. Pods narrowly linear, closely 

 oppressed to the axis of the raceme, one-half to three- 

 fourths of an inch long. Seeds dark brown, pungent. 



Pollinated by flies and bees. Nectar-bearing. Stamens 

 mature before the stigma. 



Three common Mustards linger in our fields and 

 wander along our roadsides. The first is an April 

 blossom continuing into May. This is the Winter 



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