628 



THE FORMS OF TISSUES 



[CH. 



transverse one, but is a portion of a cylindrical wall (2) cutting off 

 one corner of the mother-cell. The cell so cut off is now a certain 

 segment of a circle, with an arc of approximately 120°; and its 

 next division will be by means of a curved wall cutting it into a 



-A^ 



Fig. 276. Diagrammatic development of stomata in hyacinth. 



triangular and a quadrangular portion (3). The triangular portion 

 will continue to divide in a similar way (4, 5), and at length (for 

 a reason which is not yet clear) the partition wall between the 

 new-formed cells splits, and again we have the phenomenon of a 



Diagrammatic development of stomata in Seduni. 

 (Cf. fig. in Sachs's Botany, 1882, p. 103.) 



"stoma" with its attendant guard-cells. In Fig. 277 are shewn the 

 successive stages of division, and the changing curvatures of the 

 various walls which ensue as each subsequent partition appears, 

 and introduces a new tension into the system. Among the oblong 



