22O 



A TEXT-BOOK OF BOTANY. 



usually formed as a modification of the cell-wall, and, according 

 to Solereder, it seems to occur in the contents of the cell in only 

 the following families : (Enotheraceae. Rubiaceae, and Vitaceae, in 



A 



FlG. 119. Cell-wall mucilage. A, transverse section of seed-coat of flaxseed treated 

 with water, showing the swelling of the mucilaginous layer situated beneath the cutin; 

 B, section of Althaea root showing three large mucilage-cells; C, transverse section of elm 

 bark showing four large mucilage-cells. 



all of which the mucilage receptacles can be interpreted as being 

 incompletely differentiated raphide-sacs, i.e., without raphides. 

 II. Cell-membrane mucilage, i.e., mucilage formed as a 



