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 Europe 

 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. — Most 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 

 stipules are wanting. 



Inflorescence and Flowers. — The predominant type of 

 inflorescence is a terminal raceme; rarely the flowers are 

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



323 



Fig. 131. — Cruciferae. Floral 

 diagram above; flower in median 

 longitudinal section below. 



