lot 



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

 a piece of very young epidermia, showing the early etagea of the process. The nn- 

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

 formed first, then 2, 8, and last 3, 3 ; the. cell enclosed by these 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 

 8, i. 8, then by 3, 3, and 4, 4 ; '^asily the cell thus formed bec<me divided by a middle 

 partition, which soon split, and thus formed the opening of the stoma.- ' "— °— >• ■ 



s 



-After Sachs. 



Fig. 92d. Fio. 92ji. 



rig. 92.— Devdopment of thestomata of the leaf of HywAntKus orientalis, seen in 

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

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

 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.— Alter Sachs. 



