448 BOTANICAL GAZETTE [November 



the dissepiment, with which it forms one continuous tissue, the 

 only noticeable difference being that the cells are somewhat smaller. 



Dissepiment (fig. 4). — This transparent papery tissue at once 

 attracts attention, being made up of two parquetry-like epidermal 

 layers of elongated, pitted cells between which is an inconspicuous 

 empty parenchyma. The cells of one epidermis frequently cross 

 those of the other, which at once distinguishes the dissepiment from 

 the endocarp. The walls are approximately straight except at the 

 free edge of the dissepiment, where they become sinuous, acquiring 

 beautiful irregular shapes. The contour of the cell varies greatly 

 with the focus, owing to irregularities of the end walls. 



Characteristic elements. — The tissues which are of chief 

 value in the identification of flax fruit in ground products, such as 

 mixed cattle feed, are the elongated, thick-walled cells of the 

 hypoderm with projections (figs. 2 and 3, hy 1 ), the accompanying 

 cells each containing a single crystal (cr), and the transparent dis- 

 sepiments with elongated cells (fig. 4), those of the two epidermal 

 layers often crossing at an angle. 



from the elements 



er material likely 



Washington, D.C. 



