101 



F;g. 91. The development of the etomata of the leaf of Sedum purpurasctns. A, 

 a piece of very young epidermis, showing the early stages of the process. The nu- 

 merals Indicate the order of formation of the partitions ; that marked 1, 1, 1, was 

 lormed flrst, then 2, 2, and last 3, 3 ; the cell enclosed by theoe three partitions is the 

 etoma-mother-cell ; B, a fully completed stoma ; , , two original epidermis-cells 

 in the right hand one the new partition 1, 1, 1, first appeared ; this was followed by 

 2, 2, 2, then by 3, 3, and 4, 4 ; '^astly the cell thus formed becnme divided by a middle 

 partition, which Boon snlit, and thus formed the opening of the stoma. After Sachs. 





FIG. 92D. FIG. 92a. 



Fig. 92. Development of the stomata of the leaf of Hyacinthun orientalis, eeen in 

 transverse section. A, the division of the mother-cell S; e, e, epidermis-cells ; p p, 

 parenchyma-cells ; i, small intercellular cpace ; B and C, the same a little later ; />, 

 flrst separation of the two guard-cells by the splitting of the partition between them, 

 forming the opening t ; E, the fully formed stoma. x 800. Aiter Sachs. 



