Tig. 91. The development of the ftomata of the leaf of Sedum purpurasctm. A , 

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

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

 formed first, then 2, 2, and last 3, 3 ; the cell enclosed by thesie three partitions is the 

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

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

 i, S. 2, then by 3, 3, and 4, 4 ; ".asily tho cell thus formed bee >me divided l>y a middle 

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



FIG. 92i). FIG. 92n. 



Fig. 92. Development of thestomata of the leaf of Hyacinthu* orientalls, seen in 

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

 parenchyma-cells ; i, small intercellular -pace ; B and C, the sanie a little later ; i, 

 first 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. After Sachs. 



