TISSUES FOR SYNTHESIS 



139 



Lysigenous cavities usually show traces of the parti- 

 ally disintegrated cells in the form of projecting frag- 

 ments of wall. 



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Plate 50. — Secretion Cells. 



1. Unicellular secretion cells, Galangal rhizome. 2. Vittae, secretion cavities, 

 Fennel fruit. 3. Mucilage cells. Mustard, seed. (Surface view.) 4. Mucilage 

 cells, Mustard seed. (Sectional view.) 



Unicellular Secretion Cells. — Individual cells may 

 function as secreting organs. Unicellular secretion 

 cells differ from secretion cavities and oil ducts in 



