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HISTOLOGY OF MEDICINAL PLANTS 



vascular bundle, and between the ribs one or more secretion 

 cavities. The vascular bundles are small and are surrounded by 

 irregular-shaped mesocarp cells. 



The secretion cavities (Fig. 7) are oval in form and the tissue 

 bordering the cavity is reddish brown in color. The mesocarp 

 cells around the secretion cavities are more elongated than the 

 other mesocarp cells. 



Endocarp. The endocarp ceils are three layers in thickness. 

 These cells are elongated transversely (Fig. 4). 



Spermoderm. The cells of the spermoderm are indistinct, 

 compressed, and dark brown in color (Fig. 5) . 



Endosperm. The endosperm cells (Fig. 6) make up the greater 

 part of the fruit. The walls which are common to two cells 

 are thick, non-beaded, and non-pitted, and the cavities of the 

 cells are filled with aleurone grains. 



Embryo. The embryo cells, which show only in certain 

 sections, are similar to endosperm cells. 



In .anise, hops, sumac, and cumin fruits are characteristic 

 hairs. 



In star anise, sabal, allspice, cubeb, pepper, juniper, buck- 

 thorn, and phytolacca fruits are stone cells. 



In cubeb, pepper, and cardamon are characteristic masses of 

 aggregate starch. 



In sabal, allspice, and juniper are characteristic secretion cells. 



In all the umbelliferous fruits, with the exception of conium, 

 are yellow to brown secretion cavities. 



In cubeb and pepper is aggregate starch. Colocynth con- 

 tains many single and double spiral vessels. 



Bitter orange contains solitary crystals and spongy par- 

 enchyma. 



When studying fruits we must consider the nature of the 

 epicarp cells — whether simple or modified as papillae or hairs; 

 the form and structure of the mesocarp cells; the number, size, 

 and structure of the vascular bundle; the size and number of 

 the secretion cells or cavities; the number of layers and the 

 structure of the endocarp cells; the number of layers of stone 

 cells — when present; the color and width of the spermoderm 

 layer; the structure and cell contents of the endosperm cells; 

 the nature of the embryo cells, and the nature of the cell contents. 



