742 BOTANY AND PHARMACOGNOSY. 



which together constitute the endosperm. The embryo makes up 

 the greater portion of the seed, and the cells contain aleurone 

 grains with fixed oil. 



Ground White Must.a^rd or white mustard flour is prepared 

 from the seed of Sinapis alba with or without the removal of a 

 part of the seed-coat (hulls) and the fixed oil. In fact, not infre- 

 quently mustard seed-cake is employed. 



Prepared Mustard (German Mustard, French Mustard or 

 Mustard Paste) is a paste composed of a mixture of ground 

 mustard (either Sinapis alba or Brassica nigra, or both), salt, 

 spices and vinegar. It should contain not more than 24 per cent. 



Fig. 294. White mustard. Surface view of the different tissues as seen in the powder: 

 ep, polygonal cells of the outer epidermis showing mucilage lamellae and the reduced lumen 

 due to swelling of the lamellas; se, coUenchymatic cells beneath the epidermis; b, elongated 

 stone cells (so-called beaker cells); i, parenchyma cells beneath the stone cells, which are 

 distinguished from the corresponding layer in a number of other seeds by not containing 

 any pigment; P, cells of endosperm containing aleurone; C, tissue of cotyledon containing 

 aleurone grains and oil. — After Moeller. 



of oil; not less than 35 per cent, of protein substances, and not 

 more than 12 per cent, of crude fiber. Prepared mustard is some- 

 times adulterated with white mustard hulls separated from the 

 seed before expression of the fixed oil. 



Allied Plamt. — In Indian Colza {Brassica campestris Sarson) 

 the epidermis forms a homogeneous layer, a sub-epidermal layer 

 not being present. 



75. PEPO. — Few ellipsoidal starch grains 2 to 4 /x in diam- 

 eter in cells of outer epidermis and endosperm ; charac- 

 teristic, ellipsoidal, lignified, thick- walled cells, from 45 to 100 /i 

 in diameter and with simple pores ; yellow pigment cells of seed- 

 coat ; oil and protein grains in embryo. 



