RAPHANUS SATIVUS 



xgi 



two is the most common, including the Scarlet Globe and many 

 other leading varieties grown in the United States. The color may 

 be yellow, golden brown, cinnamon, russet, or walnut brown. 

 There is also considerable variation in size, the dimensional range 

 being 3.6 to 4.1 mm. in length, x.y to 3.3 mm. in breadth, and x.i 

 to 1.3 mm. in thickness. 



Fig. 144. A-C, three common forms of seed ; A, heart-shaped ; B, oval or egg-shaped ; C, 

 long-oval ; D, transection of seed coat and endosperm showing principal layers ; E, surface 

 view of cells of same: i, epidermis; i, outer parenchyma; 3, palisade cells; 4, pigment 

 layer; 5, endosperm; and 6, hyaline layer. (Redrawn and rearranged after Kondo, Ohara 

 Institute.) 



The outer surface of the seed coat is pitted, and the polygonal 

 reticulations are five or six-sided, varying in degree of prominence 

 and size depending upon the variety. The epidermal layer consists 

 of tabular cells which have thin or sometimes thick, lamellate 

 walls. Underlying them is a subepidermal parenchymatous zone 

 comprised of a series of tangentially oriented cells that are strongly 

 compressed and have thin golden-brown walls. The third zone 

 is made up of palisade cells which form the most conspicuous layer 

 of the seed coat owing to the fact that the inner walls, or at least 

 the inner portion of the lateral walls, are more or less strongly 



