PLANT ORGANS AND ORGANISMS 



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the Epidermal Daughter-cell. The latter, upon maturing, becomes a 

 normal epidermal cell. A partition is laid down lengthwise through 

 the Stoma Mother-cell dividing it into two stomatal daughter-cells. 

 The wall laid down lengthwise splits and thus forms the orifice of the 

 stoma; the cells on either side of the orifice are called Guard Cells. 



FIG. 89. Types of stomatal apparatuses and neighboring cells from different 

 sources. In A, a portion of the lower epidermis of Easter Lily leaf. The sto- 

 matal apparatus is surrounded by neighboring cells that are similar to other 

 epidermal cells adjacent to them; in B, lower epidermis of Senna leaflet, note 

 the two neighboring cells parallel to the guard cells, one being larger than the 

 other; C, lower epidermis of Coca leaf showing two neighboring cells, parallel 

 to the guard cells but nearly equal in size as well as papillated regular epidermal 

 cells; D, lower epidermis of Pilocarpus showing rounded stomatal apparatus 

 and four crescent-shaped neighboring cells; E, lower epidermis of Uva Ursi, 

 showing eight neighboring cells arranged radiately around stomatal apparatus; 

 F, lower epidermis of Stramonium. 



These, while at first flat and inoperative, soon become bulged and 

 crescent-shaped. This mode of development is seen in Squill, 

 Hyacinth, Daffodil, Sambucus, Silene, etc. 



Second Type. After the cutting off of the stomal mother-cell 

 there are cut off on either side portions of neighboring epidermal cells 

 which form subsidiary cells to the stoma. This condition is seen in 

 Graminece, Cyperacece, Juncacece, in various species of Aloe, Musa and 

 Proteacea. 



