208 



A TEXT-BOOK OF BOTANY. 



TANNIN IDIOBLASTS were first observed by Zopf in a number 

 of genera of the Fumariacese (Fig. 115). These are somewhat 

 analogous to and resemble the latex or pigment cells in the Papa- 

 veraceae. They develop in the meristematic cells of certain tissue 

 systems and remain constant throughout the life of the plant. The 



ep 



FIG. 114. Inclusion Cells: A, section of leaf or Pistacia Lentiscus showing numerous 

 inclusion cells (in) in the upper palisade layer and cells of mesophyll; calcium oxalate 

 (kr) ; palisade layers (pa) ; loose mesophyll (m) ; fibro vascular bundle (i) ; upper epidermis 

 (ep) ; granules of fatty substance (i); lower epidermis (ep) ; stoma (sp). B, Inclusion cells 

 or tubes (k, 1, m) in the fruit of the date palm; k, showing a homogeneous amorphous 

 content; 1 and m, separation of irregular inclusion masses in form of projections from the 

 wall. After Hanausek. 



cells vary in shape, composition of wall, and color of contents. 

 They may be either short, isolated cells or occur in chains ; or 

 they may become elongated, resembling fibers. The walls may be 

 composed of cellulose or contain a certain amount of lignin or 

 suberin. Some of the cells may contain a nucleus. The cell-sap 



