CHAPTER XXV 



CRUCIFER^ (Mustard Family) 



This family is of world-wide distribution. There are in 

 the neighborhood of 2,000 species in 180 genera. The largest 

 number of genera and species is found in southern FAirope 

 and Asia Minor. They are 

 found from low to high latitudes 

 and from low to high altitudes. 



Many of the genera yield crop 

 plants, such as cabbage, turnip, 

 rutabaga, rape, black mustard, 

 white mustard, radish, water 

 cress and horse radish, while a 

 number of genera include per- 

 nicious weeds, such as penny 

 cress, wild mustard or charlock, 

 shepherds purse, false flax, and 

 tansy mustard. 



Stems, Leaves. — ]\rost mus- 

 tards are herbaceous; a few are 

 woody. The sap is usually 

 watery and acrid. The leaves 

 are alternate, simple, and vari- 

 ously lobed or dissected. The 

 sti[)ules are wanting. 



Inflorescence and Flowers.— The predominant t\[)e of 

 injloresccnce is a terminal raceme; rarely the [lowers are 

 solitary at the end of a scape. The mustard jloiver is char- 

 323 



Cruciferai. Floral 

 diagram above; flower in median 

 longitudinal section below. 



