FLAXSEED 



351 



consisting of from 6 to 10 rows of cells, surrounding the two large 

 plano-convex cotyledons; the cells of both the endosperm and the 

 cotyledons contain a fixed oil and aleurone grains, the latter being 

 from 0.003 to 0.020 mm. in diameter. 



Linseed or Flaxseed Meal. (Fig. 153.) Lemon-yellow; frag- 

 ments of seed-coat with mucilaginous epidermal cells; sub-epidermal 

 tissue composed of two rows of yellowish cells with rather large inter- 

 cellular spaces; a layer of sclerenchymatous fibers, which are 0.100 

 to 0.250 mm. in length and about 0.010 mm. in diameter and with 

 numerous simple pores; several layers of obliterated cells; and a 

 layer of pigment cells which are more or less tabular or polygonal, 

 tangentially elongated and with a reddish- or yellowish-brown pig- 

 ment, which is colored dark blue with solutions of ferric chloride. 



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FIG. 153. Ground flaxseed: p, epidermis; c, epidermal cells with broken cuti- 

 nized layer; E, parenchyma cells beneath the epidermis; /, short scleren- 

 chymatous fibers; qu, colorless cells beneath the sclerenchymatous fibers; 

 g, pigment cells with thick, porous walls and yellowish-brown contents; C, 

 cells of cotyledons containing aleurone grams. After Moeller. 



The endosperm is made up of 2 to 6 layers of cells containing oil and 

 difficultly distinguishable protein grains. The embryo contains con- 

 siderable oil and large aleurone grains 0.010 to 0.020 mm. in diam- 

 eter, the crystalloids of which can be more readily discerned on 

 treating the material first with chloroform and then mounting in 

 an iodin solution. Flaxseed does not contain starch and the com- 

 mercial product should not show more than 10 starch grains to a milli- 

 gram of powder; it should yield not less than 30 per cent of a sapon- 

 ifiable oil, and not more than 6 per cent of ash. 



Ground flaxseed is sometimes infested by maggots. In order to 



