VEGETABLE POWDERS 



499 



Fig. 179. BLACK MUSTARD. Transverse section through the seed coat 

 (testa). Compare with the seed coat tissues of the white mustard, a, epidermal 

 layer; 6, hypodermal palisade cells (note the variation in length); c, dark colored 

 layer of cells; d, beginning of the endosperm tissue. The seed coat tissue of rape 

 seed is similar to that of black mustard. 



