101 



Tig. 91.— The development of the fitomata of the leaf of Sedum purpurascgns. A, 

 a piece of very young epidermis, showing the early stages of the process. Tbe,na- 

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

 lormed first, then 2, 2, and last 3, 3 ; the cell enclosed by theoe 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 

 2, 2. 2j then by 3, 3, and 4, 4 ; '-astly the cell thus formed became divided by a middle 

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



Fio. 92d. Fig. 92e. 



Fig. 92.— Development of the stomata of the leaf of Hyadnthus orientalise seen in 

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

 parenchyma-cell 8 ; i, small intercellular epace : B and C, the same a little later ; z), 

 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.— Atter Sachs. 



